Jamb Chemistry Past Questions and Answers

Question 91:

• JAMB 1978

The normal boiling point of a liquid is defined as

A. The temperature at which its vapour pressure equals the atmospheric pressure
B. The temperature at which bubbles begin to form
C. The temperature at which the vapour pressure equals 1 temperature
D. The temperature at which the rate of condensation of vapour equals the rate of vaporisation of the liquid
E. The temperature at which the space above the liquid is saturated

Question 92:

• JAMB 1978

Which of the following compounds will form a solution if exposed to air?

A. Na₂CO₃.10H₂O
B. NaNO₃
C. CuSO₄
D. CaCl₂
E. Na₂SO₄.10H₂O

Question 93:

• JAMB 1978

The most common type of chemical reaction which alkanes undergo is

A. Substitution
B. Addition
C. Condensation
D. Polymerisation
E. Double decomposition

Question 94:

• JAMB 1978

Consider the following exothermic reaction
2SO_2(g) + O_2(g) ↔ 2SO_3(g)
If the temperature of the reaction is reduced from 800°C to 500°C, an no other change takes place, then

A. The reaction rate increases
B. Concentration of SO₃ decreases
C. Concentration of SO₃ increases
D. SO₂ gas becomes unreactive
E. O₃ gas becomes unreactive

Question 95:

• JAMB 1978

If excess zinc is added to a bluish green solution of copper (II) sulphate, and the excess zinc filtered off after completion of reaction, a colourless solution is obtained because

A. Both zinc and copper are metals
B. The sulphate radical and the zinc ion are divalent
C. Zinc is more electropositive than copper
D. Both zinc and copper form depositive ions in solution
E. Zinc is a reducing agent