Jamb Chemistry 1991 Past Questions and Answers

Question 26:

• JAMB 1991

2H2S(g) + SO2(g) → 3S(s) + 2H2O(I). The above reaction is?

A. A redox reaction H₂S is the oxidant and SO₂ is the reductant
B. A redox reaction in which SO₂ is the oxidant and H₂S is the reductant
C. Not a redox reaction because there is no oxidant in reaction equation
D. Not a redox because there is no reductant in the reaction equation

Question 27:

• JAMB 1991

Magnesium (IV) oxide is known to hasten the decomposition of hydrogen peroxide. Its main action is to?

A. Increase the surface area of the reactants
B. Increase the concntration of the reactants
C. Lower the activation energy for the reaction
D. Lower the heat of reaction, ∆H, for the reaction

Question 28:

• JAMB 1991

1.1 g of CaCI2 dissolved in 50 cm3 of water caused a rise in temperature of3.4°C. The heat of reaction, ∆H for CaCI2 in kj per mole is?
(Ca = 40, CI = 35.5, specific heat of water is 4.18 jk-1

A. -71.1
B. -4.18
C. +71.1
D. +111.0

Question 29:

• JAMB 1991

NO_(g) + CO_(g) ↔ (1)/(2)N_2(g) + CO_2(g) ∆H = -89.3 kj.
What conditions would favour maximum conversion of nitrogen (II) oxide and carbon (II) oxide in the reaction above?

A. Low temperature and high pressure
B. High temperature and low pressure
C. High temperature and high pressure
D. Low temperature and low pressure

Question 30:

• JAMB 1991

Which of the following equilibria is unaffected by a pressure change?

A. 2NaCI(s) ↔ 2Na _(I) + CI_2(g)
B. H _2(g) + I_2(g) ↔ 2HI_(g)
C. 2O_3(g) ↔ 3O_2(g)
D. 2NO_2(g) ↔ N₂O_4(g)