ICSE Class 10 Chemistry Paper Answer Key 2024
ICSE Class 10 Chemistry exam has been successfully completed today from 11:00 AM to 1:00 PM conducted by the Council for Indian School Certificate Examinations (CISCE). This was Science Paper 2 for the ICSE Exam 2024. In this article, you will get the ICSE Class 10 Chemistry question paper 2024 along with its answer key with explanation. Students who appeared for the ICSE Chemistry exam can verify their answers using the answer key provided here.
CHEMISTRY
(Science Paper 2)
ICSE Board Class 10 Exam: 2024
GENERAL INSTRUCTIONS
Read the following instructions very carefully and follow them:
(i) Duration for the Test is 2 hours.
(ii) Maximum Marks for Section-A and B is 40 each.
(iii) The intended marks for questions or parts of questions are given in brackets [ ].
(iv) Section A is compulsory. Attempt all questions from this section.
(v) Attempt any four questions from Section B.
(vi) Use of calculator is not permitted.
(vii) It is mandatory to use Blue/Black ballpoint pen to write the answers on the paper provided separately.
SECTION-A(40 Marks)
Question 1: Choose the correct answers to the questions from the given options.
Unsaturated hydrocarbons undergo:
A. Addition reaction.B. Substitution reaction.
C. Oxidation reaction.
D. Redox reaction.
Answer
A. Addition reaction.
Explanation: Unsaturated hydrocarbons undergoes the addition reaction easily because the double or triple bond will convert into a single bond. That means unsaturated hydrocarbons becomes saturated hydrocarbons.
CH2 = CH2 + H2 → CH3 - CH3
CH ≡ CH + 2H2 → CH3 - CH3
In the 2nd period Neon has maximum Ionization Potential because:
A. It has unstable electronic configuration.B. It easily accepts electrons.
C. It easily loses electrons.
D. The outer most shell is completely filled.
Answer
D. The outer most shell is completely filled.
Explanation: Neon has completely filled outermost shell (2s22p6). Thus it is highly stable and therefore it requires high amount of energy to lose an electron from its outer shell, resulting in a high Ionization Potential.
Copper, Zinc and Tin are the metals alloyed to form:
A. Duralumin.B. Brass.
C. Bronze.
D. Solder.
Answer
C. Bronze.
The metal hydroxide which reacts with both acids and alkalis to form salt and water is:
A. Calcium hydroxide.B. Magnesium hydroxide.
C. Aluminium hydroxide.
D. Ferric hydroxide.
Answer
C. Aluminium hydroxide.
Explanation: Aluminium hydroxide is amphoteric, i.e., it has both basic and acidic properties.
Reaction of an alcohol with a carboxylic acid in the presence of concentrated H2SO4 is termed as:
A. Halogenation.B. Esterification.
C. Hydrogenation.
D. Dehydrohalogenation.
Answer
B. Esterification. An alcohol reacts with carboxylic acid in the presence of conc. H2SO4 to give sweet smelling ester.
Explanation: The reaction of an alcohol with a carboxylic acid in the presence of conc. H2SO4 forms an ester. This is termed an esterification reaction.
Conversion of Ethanol to Ethene by the action of concentrated sulphuric acid involves:
A. Dehydration.B. Dehydrogenation.
C. Dehydrohalogenation.
D. Hydrolysis.
Answer
B. Dehydrogenation.
Explanation: CH3CH2OH + conc. H2SO4 → CH2=CH2 + H2O
The oxidizing agent in the equation S + 2H2SO4 → 3SO2 + 2H2O is:
A. Sulphur.B. Sulphuric acid.
C. Sulphur dioxide.
D. Water.
Answer
B. Sulphuric acid.
Explanation: When concentrated sulphuric acid reacts with sulphur to produce sulphur dioxide gas and water. Thus, sulphuric acid (H2SO4) acts as a strong oxidizing agent as it oxidizes S into SO2.
Electron Affinity is maximum in:
A. Mg.B. Ar.
C. Li.
D. Br.
Answer
D. Br.
Explanation: Bromine has high electron affinity due to its non-metallic nature.
The compound that is not a constituent of the electrolytic mixture used in the Hall-Heroult's process is:
A. Al2O3.B. NaAlO2.
C. Na3AlF6.
D. CaF2.
Answer
B. NaAlO2
: In Hall-Heroult's process, electrolyte is a mixture of alumina, cryolite and fluorspar.
On passing ammonia gas over heated copper oxide for some time, a reddish-brown residue is left behind. What property of ammonia is demonstrated here?
A. Basic property.B. Oxidising property.
C. Reducing property.
D. Acidic property.
Answer
C. Reducing property
Explanation: When dry ammonia is passed over heated copper oxide, ammonia is oxidized to nitrogen and water. Here, copper oxide is reduced to copper and turns from black to Reddish-brown.
Rotten egg smell is due to the liberation of:
A. HCl gasB. H2S gas.
C. Cl2 gas.
D. SO2 gas.
Answer
B. H2S gas (also known as sewer gas because it is often produced by the breakdown of waste material.)
Ammonia gas is collected by downward displacement of air since ammonia is
A. very slightly soluble in water.B. heavier than air.
C. lighter than air.
D. insoluble in water.
Answer
C. lighter than air.
Which of the following would occupy 22.4 litres at S.T.P.?
1. 32g of oxygen gas2. 2 moles of hydrogen gas
3. 6.022 x 1023 molecules of ammonia
A. 1 & 2
B. 1 & 3
C. 2 & 3
D. 1,2 & 3
[Atomic weights: O=16, H=1, N=14]
Answer
B. 1 & 3.
Explanation: : 1 mole of oxygen gas = 32 g = 22.4 L (at STP)
1 mole of NH3 = 6.022 × 1023 molecules of NH3 = 22.4 L (at STP)
In the molecule of water, oxygen atom has:
A. One shared pair of electrons.B. Three shared pairs of electrons.
C. Two lone pairs of electrons.
D. One lone pair of electrons.
Answer
C. Two lone pairs of electrons.
Explanation: In a water (H2O) molecule, oxygen is bonded to two hydrogen atoms.
Total number of valence electrons present in oxygen atom is 6. It shares one electron with each hydrogen atom to form two single bonds while the remaining four electrons do not participate in any bond formation and are present as two lone pairs.
A mineral from which the metal can be extracted economically and conveniently is known as:
A. Matrix.B. Ore.
C. Flux.
D. Alloy.
Answer
B. Ore.
An ore is a mineral from which the metal can be extracted economically and conveniently.
Question 2:
(i) The following sketch represents the electroplating of an Iron cup with Nickel metal. Study the diagram and answer the following questions:
(a) During electroplating the iron cup is placed at the cathode. Why?
Answer
Iron cup is placed at cathode because during electrolytic reaction, the metal is always deposited at the cathode by gain of electrons.
(b) Name the ion that must be present in the electrolyte.
Answer
Ni+2 ions.
(c) State one condition that is necessary to ensure that the deposit is smooth, firm and even.
Answer
A low current for a longer time should be used to ensure that the deposit is smooth, firm and long lasting.
(d) Write the reaction taking place at the cathode.
Answer
Ni+2 + 2e → Ni
(e) What change would you observe at the anode?
Answer
The nickel anode (metal strip) will decrease in size as it continuously dissolves in solution by producing Ni2+ ions
(ii) Match the column A with column B
| Column A | Column B |
|---|---|
| a. Water | 1. Lithium |
| b. Alkali metal | 2. Iodine |
| c. Halogen | 3. Covalent compund |
| d. Calcium oxide | 4. Acetic acid |
| e. Weak acid | 5. Ionic compound |
| 6. Sulphuric acid |
Answer
a - 3, b - 1, c - 2, d - 5, e - 4
(iii) Complete the following sentences by choosing the correct answer from the brackets:
(a) The salt that can be prepared by Direct Combination is —–[FeCl3/FeCl2]
Answer
FeCl3
(b) The metallic oxide which can be reduced by using common reducing agents is____ [Fe2O3/Al2O3]
Answer
Fe2O3
(c) The metal nitrate which on thermal decomposition forms a black residue is_____ [zinc nitrate/copper nitrate]
Answer
Copper Nitrate
(d) During the electrolysis of copper sulphate solution, if is used as electrodes, the colour of the electrolyte does not fade___.[copper/platinum]
Answer
Copper
(c) The process of heating the concentrated ore in a limited supply or absence of air is____ [roasting/calcination]
Answer
Calcination
(iv) State the terms for the followings: [5]
(a) The group obtained by removing one hydrogen atom from parent alkane.
Answer
alkyl group (General formula of ALKANE is CnH2n +2 and that of ALKYL is CnH2n+1)
(b) Two metal plates or wires through which the current enters and leaves the electrolytic cell.
Answer
Electrodes (i.e. Anode and Cathode)
(c) The amount of substance which contains the same number of units as the number of atoms in carbon-12.
Answer
Mole
(d) The tendency of an atom to pull a shared pair of electrons towards itself in a compound.
Answer
Electronegativity
(e) The formula which represents the simplest ratio between the atoms of elements present in a compound.
Answer
Emperical Formula
(v)
(a) Give the IUPAC name of the organic compounds represented by the structural formula given below-
Answer
(a) 2,3-dichloropentane
(b) Propanoic Acid
(b) Draw the structural diagram for the following organic compounds-
1. 3-methyl pentane2. Propyne
3. Methanal
Answer
SECTION-B(40 Marks)
