Chemistry Jamb Questions

1. Which of the following statements is NOT correct?

• A. The average kinetic energy of a gas is directly proportional to its temperature
• B. At constant tempearture, the volume of a gas increases as the pressure increases
• C. The pressure of a gas is inversely proportional to its volume
• D. The temperature of a gas is directly proportional to its volume
• E. The collisions of molecules with each other are inelastic

Correct Answer: Option B

Explanation

Increasing the pressure confines the gas molecules to a smaller space, thereby reducing the volume. Reducing the pressure the other way round increases the volume of a gas. 

 

2.  Zinc Oxide is a

• A. Basic Oxide
• B. Acidic Oxide
• C. Amphoteric Oxide
• D. Neutral Oxide
• E. Reactive Oxide

Correct Answer: Option C

Explanation

No official explanation is available for this question at this time. Please check contributions posted by others below. If you can provide an explanation to help other student learn

 

3.  When sodium chloride and metallic sodium are each dissolved in water

• A. both processes are exothermic
• B. both processes are endothermic
• C. the dissolution of metallic sodium is endothermic
• D. the dissolution of metallic sodium is exothermic
• E. the dissolution of sodium chloride is explosive

Correct Answer: Option D

Explanation

When small quantities of sodium metal is added to water, there is an exothermic reaction, and they react to form sodium hydroxide and hydrogen.

4.  The periodic classification of elements is an arrangement of the elements in order of their

• A. Atomic Weights
• B. Isotopic Weights
• C. Molecular Weights
• D. Atomic Numbers
• E. Atomic Masses

Correct Answer: Option D

 

5 . In the reaction between sodium hydroxide and sulphuric acid solutions, what volume of 0.5 molar sodium hydroxide would exactly neutralise 10cm3 of 1.25 molar sulphuric acid?

• A. 5cm³
• B. 10cm³
• C. 20cm³
• D. 25cm³
• E. 50cm³

Correct Answer: Option E

 

Explanation

2NaOH+H2SO4=Na2SO4+2H2O

V x 0.5M = 2(10 x 1.25)
0.5V = 2 x 12.5
0.5V = 25
V = 250.5 = 50cm3

6. A small quantity of solid ammonium chloride (NH₄Cl) was heated gently in a test tube, the solid gradually disappears to produce two gases. Later, a white cloudy deposit was observed on the cooler part of the test tube. The ammonium chloride is said to have undergone

• A. distillation
• B. sublimation
• C. precipitation
• D. evaporation
• E. decomposition

Correct Answer: Option B

7.  Elements P, Q, R, S have 6, 11, 15, 17 electrons respectively, therefore,

• A. P will form an electrovalent bond with R
• B. Q will form a covalent bond with S
• C. R will form an electrovalent bond with S
• D. Q will form an electrovalent bond with S
• E. Q will form a covalent bond with R  

 Correct Answer: Option D

8.  

An element X forms the following compounds with chlorine; XCl₄, XCl₃, XCl₂. This illustrates the

• A. law of multiple proportions
• B. law of chemical proportions
• C. law of simple proportions
• D. law of conservation of mass
• E. law of definite proportions

Correct Answer: Option A

 

9. The oxidation state of chlorine in potassium chlorate is

• A. +1
• B. +2
• C. +3
• D. +5
• E. +7

Correct Answer: Option D

 

10.  When air which contains the gases Oxygen, nitrogen, carbondioxide, water vapour and the rare gases, is passed through alkaline pyrogallol and then over quicklime, the only gases left are;

• A. nitrogen and carbondioxide
• B. the rare gases
• C. nitrogen and oxygen
• D. nitrogen and the rare gases
• E. nitrogen, carbondioxide and the rare gases

Correct Answer: Option D