Class 12 Important Questions
PHYSICAL CHEMISTRY
☛ Which point defect in crystals does not change the density of the relevant solid ?
☛ Which point defect in its crystal units change the density of a solid ?
☛ Which point defect in its crystal units increases the density of a solid ?
☛ How do metallic and ionic substances differ in conducting electricity ?
☛ What is the number of atoms in a unit cell of a face-centred cubic crystal ?
☛ Write a feature which will distinguish a metallic solid from an ionic solid.
☛ What type of interactions hold the molecules together in a polar molecular solid ?
☛ What type of semiconductor is obtained when silicon is doped with arsenic ?
☛ Crystalline solids are anisotropic in nature.’ What does this statement mean ?
☛ Write a distinguishing feature of metallic solids.
☛ What is meant by ‘doping’ in a semiconductor ?
☛ Write a point of distinction between a metallic solid and an ionic solid other than metallic lustre.
☛ How may the conductivity of an intrinsic semiconductor be increased ?
☛ Which stoichiometric defect increases the density of a solid ?
☛ What are n-type semiconductors ?
☛ What type of stoichmetric defect is shown by AgBr and Agl ?
☛ What type of defect can arise when a solid is heated ?
☛ Why does LiCl acquire pink colour when heated in Li vapours ?
☛ How many atoms constitute one unit cell of a body-centered cubic crystal ?
☛ What type of stoichiometric defect is shown by AgCl ?
☛ What type of substances would make better Permanent Magnets:Ferromagnetic or Ferrimagnetic ?
☛ Which type of ionic substances show Schottky defect in solids ?
☛ What type of stoichiometric defect is shown by NaCl ?
☛ Why are crystalline solids anisotropic ?
☛ What is meant by ‘antiferromagnetism’ ?
☛ What is the formula of a compound in which the element Y forms ccp lattice and atoms of X occupy 1/3rd of tetrahedral voids ?
☛ A metallic element crystallises into a lattice having a pattern of AB AB … and packing of spheres leaves out voids in the lattice. What type of structure is formed by this arrangement ?
☛ A metallic element crystallises into a lattice having a ABC ABC … pattern and packing of spheres leaves out voids in the lattice. What type of structure is formed by this arrangement ?
☛ Differentiate between molarity and molality of a solution.
☛ What is meant by Reverse Osmosis ?
☛ What is meant by Osmosis ?
☛ What are isotonic solutions ?
☛ Some liquids on mixing form ‘azeotropes’. What are ‘azeotropes’?
☛ What type of intermolecular attractive interaction exists in the pair of methanol and acetone?
☛ Define the terms, ‘osmosis’ and ‘osmotic pressure’.
☛ Explain why aquatic species are more comfortable in cold water rather than in warm water.
☛ State Henry’s law and mention two of its important applications.
☛ State Raoult’s law. How is it formulated for solutions of non-volatile solutes ?
☛ Why do gases nearly always tend to be less soluble in liquids as the temperature is raised?
☛ An aqueous solution of sodium chloride freezes below 273 K. Explain the lowering in freezing points of water with the help of a suitable diagram.
☛ Derive expression for Raoult’s law when the solute is non-volatile.
☛ Define an ideal solution and write one of its characteristics.
☛ State Henry’s law. What is the effect of temperature on the solubility of a gas in a liquid?
☛ State Raoult’s law for the solution containing volatile components. What is the similarity between Raoult’s law and Henry’s law?
☛ How is the vapour pressure of a solvent affected when a non-volatile solute is dissolved in it?
☛ What is meant by positive deviations from Raoult’s law? Give an example. What is the sign of ∆mixH for positive deviation?
☛ Define azeotropes. What type of azeotrope is formed by positive deviation from Raoult’s law? Given an example.
☛ Define osmotic pressure of a solution. How is the osmotic pressure related to the concentration of a solute in a solution ?
☛ What is osmotic pressure? Why it is a colligative property ?
☛ Define osmotic pressure. How is osmotic pressure related to the concentration of a solute in a solution ?
☛ Define Colligative properties.
☛ Define the following terms:
a. Abnormal molar mass
b. van’t Hoff factor (i)
c. Mole fraction
☛ Explain Ideal and Real Solutions.
☛ A 5 percent solution (by mass) of cane-sugar (M.W. 342) is isotonic with 0.877% solution of substance X. Find the molecular weight of X.
☛ Calculate the boiling point of solution when 4 g of MgSO4 (M=120 g mol-1) was dissolved in 100 g of water, assuming MgSO4 undergoes complete ionization.(Kb for water=0.52 K kg mol-1)
☛ Calculate the mass of a non-volatile solute (molecular mass 40) which should be dissolved in 114 g octane to reduce the vapour pressure to 80%.
☛ Expalin the following terms:
a. Vapour Pressure
b. Lowering of Vapour Pressure
c. Relative Lowering of Vapour Pressure
☛ What are Positive and Negative deviation from Rault's Law
☛ Why vapour pressure of solvent is more than that of solution.
☛ What is meant by ‘limiting molar conductivity’?
☛ Express the relation between conductivity and molar conductivity of a solution held in a cell.
☛ Express the relation among the cell constant, the resistance of the solution in the cell and the conductivity of the solution. How is the conductivity of a solution related to its molar conductivity ?
☛ Write the reactions taking place at cathode and anode in lead storage battery when the battery is in use. What happens on charging the battery ?
☛ The conductivity of 0.20 M solution of KCl at 298 K is 0.025 S cm-1. Calculate its molar conductivity.
☛ The standard electrode potential (E°) for Daniel cell is +1.1 V. Calculate the ΔG° for the reaction
Zn(s) + Cu2+(aq) → Zn2+(aq) + Cu(s)
(1 F=96500 C mol-1).
☛ The standard electrode potential for Daniell cell is 1.1 V. Calculate the standard Gibbs energy for the cell reaction. (F=96,500 C mol-1)
☛ State Kohlrausch law of independent migration of ions. Why does the conductivity of a solution decrease with dilution?
☛ Calculate the time to deposit 1.27 g of copper at cathode when a current of 2A was passed through the solution of CuSO4.(Molar mass of Cu=63.5 g mol-1,1 F=96500 C mol-1)
☛ Calculate the degree of dissociation (a) of acetic acid if its molar conductivity (Λm) is 39.05 S cm2 mol-1.Given: λ°(H+)=349.6 S cm2 mol-1 and λ°(CH3COO–)=40.9 S cm2 mol-1
☛ Write the name of the cell which is generally used in hearing aids. Write the reactions taking place at the anode and the cathode of this cell.
☛ Write the name of the cell which is generally used in transistors. Write the reactions taking place at the anode and the cathode of this cell.
☛ Write the name of the cell which is generally used in inverters. Write the reactions taking place at the anode and the cathode of this cell.
☛ What are fuel cells? Explain the electrode reactions involved in the working of H2 – O2 fuel cell.
☛ How much electricity in terms of Faradays is required to produce 20 g of calcium from molten CaCl2 ?
☛ Calculate the mass of Ag deposited at cathode when a current of 2 amperes was passed through a solution of AgNO3 for 15 minutes.
☛ What type of a cell is the lead storage battery? Write the anode and the cathode reactions and the overall reaction occurring in a lead storage battery while operating.
☛ Define ‘rate of a reaction’
☛ Define ‘order of a reaction’.
☛ Define ‘activation energy’ of a reaction.
☛ Express the rate of the following reaction in terms of the formation of ammonia :
N2(g) + 3H2(g) → 2NH3(g)
☛ If the rate constant of a reaction is k=3 × 10-4 s-1, then identify the order of the reaction.
☛ Write the unit of rate constant for a zero order reaction.
☛ Define rate constant (K).
☛ For a reaction R → P, half-life (t1/2) is observed to be independent of the initial concentration of reactants. What is the order of reaction?
☛ Explain Elementary step in a reaction
☛ What do you understand by the rate law and rate constant of a reaction? Identify the order of a reaction if the units of its rate constant are :
(i) L-1 mol s-1 (ii) L mol-1 s-1
☛ What is meant by rate of a reaction? Differentiate between average rate and instantaneous rate of a reaction.
☛ Rate constant k for a first order reaction has been found to be 2.54 × 10-3 sec-1. Calculate its 3/4th life, (log 4=0.6020).
☛ Write two differences between ‘order of reaction’ and ‘molecularity of reaction’.
☛ Define the following terms :
a. Pseudo first order reaction.
b. Half life period of reaction (t1/2).
☛ Define the following terms :
a. Pseudo first order reaction.
b. Half life period of reaction (t1/2).
c. Specific rate of a reaction
☛ A reaction is of second order with respect to its reactant. How will its reaction rate be affected if the concentration of the reactant is
a. doubled b. reduced to half
☛ Write the rate equation for the reaction A2 + 3B2 → 2C, if the overall order of the reaction is zero.
☛ Write any two characteristics of Chemisorption.
☛ Why does physisorption decrease with the increase of temperature?
☛ Why are powdered substances more effective as adsorbents than their crystalline forms?
☛ Why is the ester-hydrolysis slow in the beginning and becomes faster after sometime?
☛ What is the role of desorption in the process of catalysis?
☛ What modification can you suggest in the Hardy Schulze, law?
☛ Why is it essential to wash a precipitate with water before estimating it quantitatively?
☛ What is the difference between physical adsorption and chemisorption ?
☛ What are the factors which influence the adsorption of a gas on a solid?
☛ What is an adsorption isotherm? Describe Freundlich adsorption isotherm.
☛ What do you understand by activation of adsorbent ? How is it achieved?
☛ Why is adsorption always exothermic?
☛ Discuss the effect of pressure and temperature on the adsorption of gases on solids.
☛ What is the difference between multimolecular and macromolecular colloids? Give one example of each.
☛ What are enzymes? Write in brief the mechanism of enzyme catalysis.
☛ Explain what is observed when :
a. a beam of light is passed through colloidal sol
b. an electrolyte NaCl is added to ferric hydroxide sol
c. electric current is passed through a colloidal sol ?
☛ What are emulsions? What are their different types? Give example of each type.
☛ How do emulsifires stabilise emulsion? Name two emulsifiers.
☛ Give four examples of heterogeneous catalysis.
☛ What do you mean by activity and selectivity of catalysts?
☛ Describe some features of catalysis by zeolites.
☛ What is shape selective catalysis?
☛ Explain the following terms :
a. Electrophoresis
b. Coagulation
c. Dialysis
d. Tyndall effect
☛ Give four uses of emulsions.
☛ What are micelles? Give an example of a micelle system.
☛ Explain the terms with suitable examples :
a. Alcosol
b. Aerosol
c. Hydrosol
☛ Comment on the statement that colloid is not a substance but a state of substance.
☛ What is the ‘coagulation’ process?
☛ What are lyophobic colloids? Give one example for them.
☛ Define ‘peptization’.
☛ How can a colloidal solution and true solution of the same colour be distinguished from each other?
☛ How is a sol different from an emulsion ?
☛ Write two applications of adsorption.
☛ Why do true solutions not show Tyndall effect?
☛ What is especially observed when a beam of light is passed through a colloidal solution?
☛ To which colloidal system does milk belong?
☛ Give one example each of ‘oil in water’ and ‘water in oil’ emulsion.
☛ Give one example each of sol and gel.
☛ Give one example each of lyophobic sol and lyophilic sol.
☛ What is the effect of temperature on chemisorption?
☛ What are the dispersed phase and dispersion medium in milk?
☛ A delta is formed at the melting point of sea water and river water. Why?
☛ In reference to surface chemistry, define dialysis.
☛ What are associated colloids? Given an example.
☛ Write one similarity between physisorption and chemisorption.
☛ What type of colloid is formed when a liquid is dispersed in a solid? Give an example.
☛ What is the difference between multi-molecular and macromolecular colloids?
☛ What happens in the following activities and why?
a. An electrolyte is added to a hydrated ferric oxide sol in water.
b. A beam of light is passed through a colloidal solution.
c. An electric current is passed through a colloidal solution.
INORGANIC CHEMISTRY
☛ Copper can be extracted by hydrometallurgy but not zinc. Explain.
☛ What is the role of depressant in froth-floatation process?
☛ Why is the extraction of copper from pyrites more difficult than that from its oxide ore through reduction?
☛ Out of C and CO which is a better reducing agent at 673 K?
☛ Name the common elements present in anode mud in the electro-refining of copper. Why are they so present?
☛ Write down the reactions taking place in different zones in the blast furnace during the extraction of iron.
☛ Write chemical reactions taking place in the extraction of zinc from zinc blende.
☛ State the role of silica in the metallurgy of copper.
☛ What is meant by the term “chromatography”?
☛ What criterion is followed for the selection of the stationary phase in chromatography?
☛ Describe a method for refining nickel.
☛ How can you separate alumina from silica in a bauxite ore associated with silica? Give equations, if any.
☛ How can you separate alumina from silica in a bauxite ore associated with silica? Give equations, if any.
☛ How is ‘cast-iron’ different from ‘pig iron’?
☛ Differentiate between “minerals” and “ores’.
☛ Why copper matte is put in silica lined converter?
☛ What is the role of cryolite in the metallurgy of aluminium?
☛ What is the role of cryolite in the metallurgy of aluminium?
☛ Why is zinc not extracted from zinc oxide through reduction using CO?
☛ What is the role of graphite rod in the electrometallurgy of aluminium?
☛ Why is the froth flotation method selected for the concentration of sulphide ores? What is meant by the term ‘pyrometallurgy’?
☛ What is meant by the term ‘pyrometallurgy’?
☛ Differentiate between a mineral and an ore.
☛ What type of ores can be concentrated by magnetic separation method?
☛ How is copper extracted from a low grade ore of it?
☛ Name the methods used for refining of following metals : Nickel and Titanium
☛ What types of metals are usually purified by the method of zone refining? Give an example.
☛ What is the basic principle of zone refining of metals?
☛ Name the method used for the refining of Nickel metal.
☛ What is the composition of ‘Copper matte’?
☛ Name the method used for refining of copper metal.
☛ Name the methods used for the vapour phase refining of impure titanium and nickel metals.
☛ Which reducing agent is employed to get copper from the leached low grade copper ore?
☛ What is the role of zinc metal in the extraction of silver?
☛ What is the function of SiO2 in the metallurgy of copper?
☛ Name the chief ores of aluminium and zinc.
☛ Give two examples of ligands which form coordination compounds useful in analytical chemistry.
☛ Which of the following is more stable complex and why ?[Co(NH3)6]3+ and [Co(en)3]3+
☛ What is meant by chelate effect?
☛ Why are low spin tetrahedral complexes not formed?
☛ How is the stability of a co-ordination compound in solution decided ?
☛ [Fe(H2O)6]3+ is strongly paramagnetic whereas [Fe(CN)6]3- is weakly paramagnetic. Explain.
☛ Give an example of linkage isomerism.
☛ Give an example of coordination isomerism.
☛ Give an example of ionization isomerism.
☛ Write down the formula of Tetraamineaquachloridocobalt(III) chloride.
☛ Indicate the types of isomerisms exhibited by the complex [Co(NH3)5 (NO2)] (NO3)2.
☛ What type of bonding helps in stabilishing the a-helix structure of proteins ?Which complex ion is formed when undecomposed AgBr is washed with hypo solution in photography ?
☛ Give IUPAC name of the ionization isomer of [Ni(NH3)3NO3]Cl.
☛ Explain why [Co(NH3)6]3+ is an inner orbital complex whereas [Ni(NH3)6]2+ is an outer orbital complex.
☛ Write the IUPAC name of the complex [Cr(NH3)4Cl2]+. What type of isomerism does it exhibit?
☛ When a co-ordination compound CrCl3.6H2O is mixed with AgNO3, 2 moles of AgCl are precipitated per mole of the compound. Write
a. Structural formula of the complex.
b. IUPAC name of the complex.
☛ For the complex [Fe(en)2Cl2] Cl, identify
a. the oxidation number of iron
b. the hybrid orbitals and the shape of the complex
c. the magnetic behaviour of the complex
d. the number of geometrical isomers
e. whether there is an optical isomer
f. name of the complex
☛ Compare the following complexes with respect to their shape, magnetic behaviour and the hybrid orbitals involved:
a. [CoF4]2–
b. [Cr(H2O)2(C2O4)2]–
c. [Ni(CO)4]
☛ Giving a suitable example for each, explain the following :a. Crystal field splittingb. Linkage isomerismc. Ambidentate ligand
☛ Explain the following :
a. Low spin octahedral complexes of nickel are not known
b. The π-complexes are known for transition elements only
☛ Explain the following terms giving a suitable example in each case:
a. Ambident ligand
b. Denticity of a ligand
c. Crystal field splitting in an octahedral field
☛ Give the formula of each of the following coordination entities :a. Co3+ ion is bound to one Cl–, one NH3 molecule and two bidentate ethylene diamine (en) molecules
b. Ni2+ ion is bound to two water molecules and two oxalate ions.
☛ State a reason for each of the following situations:
a. Co2+ is easily oxidized to Co3+ in presence of a strong ligand
b. CO is a stronger complexing reagent than NH3
c. The molecular shape of [Ni(CO)4] is not the same as that of [Ni(CN)4]2-
☛ Give two examples of coordination compounds used in industries.
☛ What is meant by crystal field splitting energy ? On the basis of crystal field theory, write the electronic configuration of d4 in terms of t2g and eg in an octahedral field when
a. Δ0 > P
b. Δ0
☛ How is a double salt different from a complex ?
☛ Draw the structure of cis isomer of [CO(NH3)4Cl2]+
☛ Using Valence bond theory explain the geometry and magnetic behaviour by [Cr(NH3)6]3+
ORGANIC CHEMISTRY
☛ A solution of KOH hydrolyses CH3CHClCH2CH3 and CH3CH2CH2CH2Cl. Which one of these is more easily hydrolysed ?
☛ Predict the order of reactivity of the following compounds in SN1 reaction :
C6H5CH2Br, C6H5C(CH3) (C6H5)Br, C6H5CH(C6H5)Br, C6H5CH(CH3)Br
☛ Give a chemical test to distinguish between C2H5Br and C6H5Br.
☛ Arrange the following in increasing order of boiling point:
a. CH3CH2CH2CH2Br
b. (CH3)3.Br
c. (CH3)2CH.Br
☛ What happens when CH3 — Br is treated with KCN ?
☛ What happens when ethyl chloride is treated with aqueous KOH ?
☛ A hydrocarbon C5H12 gives only one mono-chlorination product. Identify the hydrocarbon.
☛ Write the structure of an isomer of compound C4H9Br which is most reactive towards SN1 reaction.
☛ How are the following conversions carried out ?
a. Benzyl chloride to benzyl alcohol
b. Methyl magnesium bromide to 2-methyl- propan-2-ol
☛ Haloalkanes undergo nucleophilic substitution whereas haloarenes undergo electrophilic substitution. Explain.
☛ Chlorobenzene is extremely less reactive towards a nucleophilic substitution reaction. Give two reasons for the same.
☛ Why does p-dichlorobenzene have a higher m.p. than its o- and m-isomers ?
☛ Why is (±)-Butan-2-ol optically inactive ?
☛ Account for the following:
a. The C – Cl bond length in chlorobenzene is shorter than that in CH3 – Cl.
b. Chloroform is stored in closed dark brown bottles.
☛ Give chemical tests to distinguish between the following pairs of compounds :
a. Benzyl chloride and Chlorobenzene
b. Chloroform and Carbon tetrachloride
☛ Explain why :
a. The dipole moment of chlorobenzene is lower than that of cyclohexyl chloride.
b. Alkyl halides, though polar, are immiscible with water.
☛ Out of SN1 and SN2, which reaction occurs with
a. Inversion of configuration
b. Racemisation
☛ What are ambident nucleophiles? Explain with an example.
☛ Write the structures of the following organic halogen compounds :
a. 4-tert-Butyl-3-iodoheptane
b. 4-Bromo-3-methylpent-2-ene
☛ Write the equations for the preparation of 1-bromobutane from :a. 1-butanol
but-l-ene
☛ Which compound in each of the following pairs will react faster in SN2 reaction with —OH ?
☛ Which alkyl halide from the following pair is Chiral and undergoes SN1 reaction faster?a. (CH3)2CBrb. CH3CH2CHBrCH3
☛ How will you carry out the following conversions:
a. 2-Bromopropane to 1-bromopropane
b. Benzene to p-chloronitrobenzene
☛ State one use each of DDT and iodoform.
☛ Which compound in the following couples will react faster in SN2 displacement and why ?
1-bromopentane or 2-bromopentane
l-bromo-2-methylbutane or 2-bromo-2-methylbutane
☛
Haloalkanes easily dissolve in organic solvents, why ?
☛ What is known as a racemic mixture? Give an example.
☛ Of the two bromoderivatives, C6H5CHBr-CH3 and C6H5CHBr-C6H5, which one is more reactive in SN1 substitution reaction and why ?
☛ Rearrange the compounds of each of the following sets in order of reactivity towards SN2 displacement :
a. 2-Bromo-2-methylbutane, 1-Bromopentane, 2-Bromopentane
b. l-Bromo-3-methylbutane, 2-Bromo-2-methyl-butane, 3-Bromo-2-methylbutane
c. 1-Bromobutane, l-Bromo-2,2-dimethyl-propane, l-Bromo-2-methylbutane
☛ Although chlorine is an electron withdrawing group, yet it is ortho-, para-directing in electrophilic aromatic substitution reactions. Explain why it is so ?
☛ What is meant by chirality of a compound? Give an example.
☛ The dipole moment of chlorobenzene is lower than that of cyclohexyl chloride.
☛ Grignard’s reagents should be prepared under anhydrous conditions. Explain.
☛ Alkyl halides, though polar, are immiscible with water.
☛ Give reasons for the following :a. Ethyl iodide undergoes SN2 reaction faster than ethyl bromide.b. (±) 2-Butanol is optically inactive.c. C—X bond length in halobenzene is smaller than C—X bond length in CH3—X.
☛Give reasons :
a. n-Butyl bromide has higher boiling point than f-butyl bromide.b. Racemic mixture is optically inactive.
c. The presence of nitro group (-NO2) at o/p positions increases the reactivity of haloarenes towards nucleophilic substitution reactions.
☛ How can the following conversions be carried out :
a. Aniline to bromobenzene
b. Chlorobenzene to 2-chloroacetophenone
c. Chloroethane to butane
d. Chlorobenzene to biphenyl
e. Propene to 1-iodopropanef
f. 2-bromobutane to but-2-ene
☛ What happens when
a. Chlorobenzene is treated with Cl2/FeCl3
b. Ethyl chloride is treated with AgNO2
c. 2-bromopentane is treated with alcoholic KOH ?
☛ Following compounds are given to you:2-Bromopentane, 2-Bromo-2-methylbutane, 1-Bromopentanea. Write the compound which is most reactive towards SN2 reaction.
b. Write the compound which is optically active.
c. Write the compound which is most reactive towards β – elimination reaction.
☛ Which of the following has the highest dipole moment:
CH2Cl2, CHCl3, CCl4
☛ Why is sulphuric acid not used during the reaction of alcohols with Kl ?
☛ Among the isomeric alkanes of molecular formula C5H12, identify the one that on photochemical chlorination yields
a. A single monochloride
b. Three isomeric monochlorides
c. Four isomeric monochlorides.
☛ Arrange each set of compounds in order of increasing boiling points:
a. Bromomethane, bromoform, chloromethane, dibromomethane
b. 1 – Chloropropane, isopropyl chloride, 1 – chlorobutane
☛ A hydrocarbon C5H10 does not react with chlorine in dark but gives a single monochloro compound C5H9Cl in bright sunlight. Identify the hydrocarbon.
☛ Write the equations for the preparation of 1 -iodobutane from
a. 1-butanol
b. 1-chlorobutane
c. but-1-ene
☛ Which compound in each of the following pairs will react faster in SN2 reaction with OH– ?
a. CH3Br or CH3l
b. (CH3)3CCI or CH3Cl ☛ predict all the alkenes that would be formed by dehydrohalogenation of the following halides with sodium ethoxide in ethanol and identify the major alkene :
a. 1-Bromo-1-methylcyclohexane
b. 2-Chloro-2-methylbutane
c. 2, 2, 3-Trimethyl-3-bromopentane
☛ How will you bring about the following conversions ?
a. Ethanol to but-1 -yne
b. Ethane to bromoethene
c. Propeneto 1-nitropropane
d. Toluene to benzyl alcohol
e. Propene to propyne
f. Ethanol to ethyl fluoride
g. Bromomethane to propanone
h. But-1 -ene to but-2-ene
i. 1-Chlorobutane ton-octane
j. Benzene to biphenyl
☛ p-Dichlorobenzene has higher m.p. and solubility than those of o- and m-isomers. Discuss.
☛ How can the following conversions be carried out ?
a. Propene to propan-1 -ol
b. Ethanol to but-1 -yne
c. 1 -Bromopropane to 2-bromopropane
d. Toluene to benzyl alcohol
e. Benzene to 4-bromonitrobenzene
f. Benzyl alcohol to 2-phenylethanoic acid
g. Ethanol to propanenitrile
h. Aniline to chlorobenzene
i. 2-Chlorobutane to 3,4-dimethylhexane
j. 2-Methyl-1 -propene to 2-chloro-2- methylpropane
k. Ethyl chloride to propanoic acid
l. But-1-ene to n-butyliodide
m. 2-Chloropropaneto 1-propanol
n. Isopropyl alcohol to iodoform
o. Chlorobenzene to p-nitrophenol
p. 2-Bromopropane to 1-bromopropane
q. Chloroethane to butane
r. Benzene to diphenyl
s. ferf-Butyl bromide to isobutyl bromide
t. Aniline to phenylisocyanide
☛ The treatment of alkyl chlorides with aqueous KOH leads to the formation of alcohols but in the presence of alcoholic KOH, alkenes are major products. Explain.
☛ Primary alkyl halide C4H9Br (A) reacted with alcoholic KOH to give compound (B). Compound (B) is reacted with HBr to give (C) which is an isomer of (A). When (A) is reacted with sodium metal it gives compound (D). C8H18 which is different from the compound formed when n-butyl bromide is reacted with sodium. Give the structural formula of (A) and write the equations for all the reactions.
☛ What happens when
a. n-butyl chloride is treated with alcoholic KOH
b. bromobenzene is treated with Mg in the presence of dry ether
c. chlorobenzene is subjected to hydrolysis
d. ethyl chloride is treated with aqueous KOH
e. methyl bromide is treated with sodium in the presence of dry ether
f. methyl chloride is treated with KCN ?
☛ Why is an alkylamine more basic than ammonia ?
☛ Arrange the following compounds in an increasing order of basic strengths in their aqueous solutions:
NH3, CH3NH2, (CH3)2NH, (CH3)3N
☛ Give the IUPAC name of H2N — CH2—CH2—CH=CH2.
☛ Arrange the following compounds in an increasing order of their solubility in water:
C6H5NH2, (C2H5)2NH, C2H5NH2
☛ Give a chemical test to distinguish between ethylamine and aniline.
☛ Write the structure of 2-aminotoluene.
☛ Write the structure of n-methylethanamine.
☛ Write the structure of prop-2-en-l-amine.
☛ How may methyl bromide be preferentially converted to methyl isocyanide ?
☛ The conversion of primary aromatic amines into diazonium salts is known as
☛ Out of CH3—NH2 and (CH3)3N, which one has higher boiling point?
☛ Arrange the following in increasing order of basic strength-
Aniline, p-Nitroaniline and p-Toluidine
☛ Give the chemical tests to distinguish between the following pairs of compounds :
a. Ethyl amine and Aniline
b. Aniline and Benzylamine
☛ Give the chemical tests to distinguish between the following pairs of compounds:
a. Methylamine and Dimethylamine
b. Aniline and N-methylaniline
☛ Describe the following giving the relevant chemical equation in each case:
a. Carbylamine reaction
b. Hofmann’s bromamide reaction
☛ Complete the following reaction equations:
a. C6H5N2Cl + H3PO2 + H2O →
b. C6H5NH2 + Br2 (aq) →
☛ How are the following conversions carried out:
a. Aniline to p-hydroxyazobenzene
b. Ethanoyl chloride to Ethanenitrile.
☛ How are the following conversions carried out ?
a. CH3CH2Cl to CH3CH2CH2NH2
b. Benzene to Aniline
☛ How would you account for the following:
a. Aniline is a weaker base than cyclohexyl amine.
b. Methylamine in aqueous medium gives reddish-brown precipitate with FeCl3.
☛ How would you account for the following:
a. Electrophilic susbstitution in case of aromatic amines takes place more readily than benzene.
b. Ethanamide is a weaker base than ethanamine.
☛ Illustrate the following reactions:
a. Sandmeyer’s reaction
b. Coupling reaction
c. Gabriel Phthalimide reaction
☛ Give chemical tests to distinguish between the following pairs of compounds:
a. Aniline and Ethylamine
b. Ethylamine and Dimethylamine
☛ Explain Aniline is a weaker base than cyclohexyl amine.
☛ It is difficult to prepare pure amines by ammonolysis of alkyl halides. Explain
☛ Complete the following reaction equations:
a. C6H5Cl + CH3COCl →
b. C2H5NH2 + C6H5SO2Cl →
c. C2H5NH2 + HNO2 →
☛ State reasons for the following:
a. pKb value for aniline is more than that for methylamine.
b. Ethylamine is soluble in water whereas aniline is not soluble in water.
c. Primary amines have higher boiling points than tertiary amines.
☛ Write chemical equations for the following conversions:
a. Nitrobenzene to benzoic acid.
b. Benzyl chloride to 2-phenylethanamine
c. Aniline to benzyl alcohol.
☛ How will you convert the following:
a. Nitrobenzene into aniline
b. Ethanoic acid into methanamine
c. Aniline into N-phenylethanamide
☛ Account for the following:
a. Primary amines (R-NH2) have higher boiling point than tertiary amines (R3N)
b. Aniline does not undergo Friedel – Crafts reaction.
c. (CH3)2NH is more basic than (CH3)3N in an aqueous solution.
☛ An aromatic compound 'A' on treatment with aqueous ammonia and heating forms compound 'B' which on heating with Br2 and KOH forms a compound 'C' of molecular formula C6H7N. Write the structures and IUPAC names of compounds A, B and C.
☛ Describe a method for the identification of primary, secondary and tertiary amines. Also write chemical equations of the reaction involved.
☛ Acetylation of aniline reduces its activation effect, why ?
☛ Explain Sandmeyer's reaction with the help of a suitable example.
☛ Write the structures of main products when aniline reacts with the following reagents:
a. Br2 water
b. HCI
c. (CH3CO)2O/pyridine
☛ Write the structures of main products when benzene diazonium chloride reacts with the following reagents:
a. H3PO2 + H2O
b. CuCN/KCN
c. H2O
☛ Give one chemical test to distinguish between the following pairs of compounds.
a. Methylamine and dimethylamine
b. Secondary and tertiary amines
c. Ethylamine and aniline
d. Aniline and benzylamine
e. Aniline and N-methylaniline
☛ How will you convert:
a. Ethanoic acid into methanamine
b. Hexanenitrile into 1-aminopentane
c. Methanol to ethanoic acid
d. Ethanamine into methanamine
e. Ethanoic acid into propanoic acid
f. Methanamine into ethanamine
g. Nitromethane into dimethylamine
h. Propanoic acid into ethanoic acid
☛ Write short notes on the following:
a. Carbylamine reaction
b. Diazotisation
c. Hofmann’s bromamide reaction
d. Coupling reaction
e. Ammonolysis
f. Acetylation
g. Gabriel phthalimide synthesis
☛ Accomplish the following conversions:
a. Nitrobenzene to benzoic acid
b. Benzene to m-bromophenol
c. Benzoic acid to aniline
d. Aniline to 2,4,6-tribromofluorobenzene
e. Benzyl chloride to 2-phenylethanamine
f. Chlorobenzene to p-chloroaniline
g. Aniline to p-bromoaniline
h. Benzamide to toluene
i. Aniline to benzyl alcohol
☛ Give plausible explanation for each of the following:
a. Why are amines less acidic than alcohols of comparable molecular masses ?
b. Why do primary amines have higher boiling point than tertiary amines ?
c. Why are aliphatic amines stronger bases than aromatic amines ?
Exercise Questions
☛ What is meant by ‘reducing sugars’?
☛ What are monosaccharides?
☛ Write the structure of the product obtained when glucose is oxidised with nitric acid.
☛ Write a reaction which shows that all the carbon atoms in glucose are linked in a straight chain.
☛ What are the expected products of hydrolysis of lactose ?
☛ Where does the water present in the egg go after boiling the egg?
☛ Name a water soluble vitamin which is a powerful antioxidant. Give its one natural source.
☛ What are three types of RNA molecules which perform different functions?
☛ What is a glycosidic linkage?
☛ What are the products of hydrolysis of sucrose?
☛ Name a water soluble vitamin which is a powerful antioxidant. Give its one natural source.
☛ Write the name of linkage joining two amino acids.
☛ Name the deficiency diseases resulting from lack of Vitamins A and E in the diet.
☛ Name one water soluble vitamin which is a powerful antioxidant. Give its one natural source.
☛ Name one oil soluble vitamin which is a powerful antioxidant and give its one natural source.
☛ Mention one important function of nucleic acids in our body.
☛ Which of the two components of starch is water soluble?
☛ Which component of starch is a branched polymer of a-glucose and insoluble in water?
☛ What are enzymes?
☛ Name two water soluble vitamins, their sources and the diseases caused due to their deficiency in diet.
☛ What are essential and non-essential amino acids in human food? Give one example of each type.
☛ State clearly what are known as nucleosides and nucleotides.Describe what you understand by primary structure and secondary structure of proteins.
☛ Why are vitamin A and vitamin C essential for us?
☛ Amino acids may be acidic, alkaline or neutral. How does this happen? What are essential and non-essential amino acids? Name one of each type.
☛ Write the structural and functional differences between DNA and RNAGive two differences between globular and fibrous proteins.
☛ How are hormones and vitamins different in respect of their source and functions?
☛ How are nucleosides different from nucleotides?
☛ What are polymers?
☛ How are polymers classified on the basis of structure?
☛ Explain the difference between Buna-N and Buna-S.
☛ Arrange the following polymers in increasing order of their intermolecuiar forces.
a. Nylon 6,6, Buna-S, Polythene
b. Nylon 6, Neoprene, Polyvinyl chloride
☛ What are natural and synthetic polymers ? Give two examples of each.
☛ Distinguish between the terms homopolymer and copolymer and give an example of each.
☛ How do you explain the functionality of a monomer?
☛ Define the term polymerisation?
☛ Is (-NH — CHR—CO-)n a homopolymer or copolymer?
☛ In which classes, are the polymers classified on the basis of molecular forces?
☛ How can you differentiate between addition and condensation polymerisatiop?
☛ Explain the term copolymerisation and give two examples.
☛ Write the free radical mechanism for the polymerisation of ethene.
☛ Define thermoplastics and thermo setting polymers with two examples of each
☛ Write the monomers used for gettingThe following polymers:
a. Polyvinylchloride
b. Teflon
c. Bakelite
☛ Write the name and structure of one of the common initiators used in free radical addition polymerisation.
☛ How is dacron obtained from ethylene glycol and terephthalic acid?
☛ What is a biodegradable polymer ? Give an example of a biodegradable aliphatic polyester.
☛ Discuss the main purpose of vulcanisation of rubber.
☛ Write the names and structures of the monomers of the following polymers:
a. Glyptal
b. Teflon
c. Nylon-6
☛ Differentiate between disinfectants and antiseptics.
☛ What are limited spectrum antibiotics? Give one example.
☛ Name the important by-products of soap industry.
☛ Why do we require artificial sweetening agents ?
☛ What are food preservatives? Name two such substances.
☛ Explain the cleaning action of soap. Why do soaps not work in hard water ?
☛ What are Cationic detergents and Anionic detergents ?
☛ Explain the following types of substances with one suitable example, for each case-
a. Food preservatives
b. Analgesics
☛ What are analgesic medicines ? How are they classified and when are they commonly recommended for use ?
☛ Explain the following terms with one suitable example in each case-
a. Enzymes
b. Antifertility drugs
☛ Why do soaps not work in hard water ?
☛ What are the main constituents of dettol ?
☛ What is tincture of iodine and what is it used for ?
☛ What are the following substances? Give one example of each one of them-
a. Tranquilizers
b. Synthetic detergents
c. Narcotic analgesics
☛ What is Broad spectrum antibiotics ?
☛ Why is bithional added to soap ?
☛ Which class of drugs is used in sleeping pills ?
☛ What class of drug is Ranitidine ?
☛ If water contains dissolved Ca2+ ions, out of soaps and synthetic detergents, which will you use for cleaning clothes ?
☛ Give two examples of macromolecules that are chosen as drug targets.
☛ What are antiseptics ? Give an example.
☛ Why is use of aspartame limited to cold foods and soft drinks ?
☛ Name the sweetening agent used in the preparation of sweets for a diabetic patient.
☛ What are biodegradable and non-biodegradable detergents? Give one example of each.
☛ Why should medicines not be taken without consulting a doctor ?
☛ What are the main constituents of Dettol ?
☛ Why is the use of aspartame limited to cold foods and drinks ?
☛ Write the therapeutic action of following on human body and mention the class of drugs to which each of these belong:
a. Ranitidine
b. Morphine
c. Aspirin
☛ Write the therapeutic action of following on human body and mention the class of drugs to which each of the these belong:
a. Equanil
b. Aspirin
c. Chloramphenicol
☛ Name a substance which can be used as an antiseptic as well as disinfectant.
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