PART - A: Multiple Choice Questions
1) The major product formed when 2-bromobutane reacts with Alcoholic KOH and heat is:
Answer: d) 2-butene
2) The percentage of helium filled in the tanks used by most scuba divers to dilute air in deep dives is:
Answer: b) 11.7
3) The common oxidation state shown by the element with atomic number 21 (Scandium) is:
Answer: a) +3
4) The main natural source of acetic acid is:
Answer: b) vinegar
5) Acetylation of salicylic acid produces a compound which has anti-inflammatory and antipyretic property. The compound is:
Answer: d) Aspirin
6) p-Hydroxyazobenzene is formed by the reaction of benzene diazonium chloride with phenol. It is:
Answer: a) an electrophilic substitution reaction
7) Doctor advised a 50 year old woman enough exposure to sunlight and addition of fish and egg yolk to her diet. Name the vitamin deficiency:
Answer: a) Vitamin D
PART - A: Match the Following (Question 13)
13) Match the elements in List I with their maximum oxidation states in List II:
| Element | Max Oxidation State |
|---|---|
| i) Thorium (Th) | e) +4 |
| ii) Protactinium (Pa) | d) +5 |
| iii) Lawrencium (Lr) | c) +3 |
| iv) Uranium (U) | b) +6 |
| v) Plutonium (Pu) | a) +7 |
Answer: Correct Option: b) i-e, ii-d, iii-c, iv-b, v-a
14) The complex [Co(NH3)5(NO2)]Cl2 (linkage isomer bound through Nitrogen) is obtained as a:
Answer: d) Yellow
15) Statement I: Alcohols are acidic in nature due to the polar O-H bond. Statement II: Alcohols are weaker acids than water.
Answer: b) Both Statement I and Statement II are correct
PART - A: Fill in the Blanks
Options: [reducing, zero, sodium alkoxide, one, pleasant, pungent]
16) Oxidation state of 'Ni' in [Ni(CO)4] is:
Answer: zero
17) In Williamson ether synthesis, an alkyl halide is allowed to react with:
Answer: sodium alkoxide
18) The carbohydrates which reduce Fehling's solution and Tollens' reagent are called as:
Answer: reducing
19) The lower aldehydes have sharp ______ odours:
Answer: pungent
20) Van't Hoff factor (i) for a non-electrolyte in a solution is:
Answer: one
PART - B: Short Answer Questions
21) What are transition elements? Give an example.
Answer: Transition elements are elements that have partially filled d-orbitals in their ground state or in any of their common oxidation states. Example: Iron (Fe) or Copper (Cu).
22) Write the SN2 mechanism involved in the conversion of chloromethane to methanol.
Answer: The SN2 mechanism involves a single-step process where the nucleophile (OH⁻) attacks the carbon atom from the side opposite to the leaving group (Cl⁻), passing through a pentacoordinate transition state.
23) What is half-life of a reaction? Represent it symbolically.
Answer: Half-life is the time required for the concentration of a reactant to decrease to half of its initial value. It is represented symbolically as t1/2.
24) List any two nitrogeneous bases commonly found in both DNA and RNA.
Answer: Adenine and Guanine (or Cytosine).
25) Write the products formed when anisole reacts with ethanoyl chloride in the presence of anhydrous AlCl3.
Answer: The reaction produces 2-methoxacetophenone (minor) and 4-methoxacetophenone (major).
PART - C: Short Answer Questions
26) Valence Bond Theory (VBT) for [Co(NH3)6]3+
Answer: Based on VBT for the Cobalt complex (Atomic No. 27):
- Hybridisation: d2sp3 (Inner orbital octahedral complex).
- Geometry: Octahedral.
- Magnetic Property: Diamagnetic (All electrons are paired due to the strong field of NH3 ligands).
27) Lanthanoid Contraction
Answer:
- Definition: The steady decrease in the atomic and ionic radii of lanthanoid elements with increasing atomic number.
- Consequences:
- Similarity in chemical properties and sizes of 4d and 5d series elements (e.g., Zr and Hf).
- Difficulty in the separation of lanthanoid elements.
28) Geometrical Isomers of [MX2(L-L)2]
Answer:
- Isomers: This complex exhibits cis and trans geometrical isomerism.
- Optically Inactive Form: The trans isomer is the optically inactive form.
29) Completed Chemical Equations
Answer:
i) 4FeCr2O4 + 8Na2CO3 + 7O2 → 8Na2CrO4 + 2Fe2O3 + 8CO2
ii) 2Na2CrO4 + 2H+ → Na2Cr2O7 + 2Na+ + H2O
iii) Na2Cr2O7 + 2KCl → K2Cr2O7 + 2NaCl
30) Cobalt Carbonyl Complex
Answer:
- IUPAC Name: Octacarbonyldicobalt(0).
- Structure:
- Bridged CO groups: There are 2 bridged carbonyl groups in the solid state structure.
31) Integrated Rate Equation for First Order Reaction
Answer: For a first order reaction, the rate constant (k) is derived as:
k = (2.303 / t) * log([R]0 / [R])
Where [R]0 is initial concentration and [R] is concentration at time t.
32) Standard Hydrogen Electrode (S.H.E.)
Answer:
- Cell Representation: Pt(s) | H2(g, 1 bar) | H+(aq, 1 M)[cite: 142].
- Half-cell Reaction: H+(aq) + e- → ½H2(g)[cite: 142].
- Diagram:
33) Ideal Solutions
Answer:
- Definition: Solutions that obey Raoult's law over the entire range of concentration.
- Characteristics:
- ΔmixH = 0 (No enthalpy change on mixing).
- ΔmixV = 0 (No volume change on mixing).
34) Factors Influencing Electrolysis Products
Answer:
- The nature of the material being electrolyzed (electrolyte).
- The type of electrodes used (inert or reactive).
- The electrode potentials of the oxidizing and reducing species.
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