Waec Chemistry 1991 Past Questions and Answers

Question 16:

• WAEC 1991

A compound which liberates carbon (IV) oxide from a hydrogentrioxocarbonate (lV) could have the molecular formula

A. C₂H₅OH
B. C ₃H ₄
C. HCOOH
D. H₂O₂
E. C₆H₆

Question 17:

• WAEC 1991

CH_4(g) + 2O_{2(g) → 2H[sub]2}O_(l) + CO_2(g) ∆H = 890KJ mo-₁ ∆H in the reaction represented by the equation above is the enthalpy of
[/sub]

A. Formation
B. Combustion
C. Solution
D. Activation
E. Neutralization

Question 18:

• WAEC 1991

Consider the reaction represented by the equation below: H_2(g) + 1_2(s) ⇌ 2HI_(g) ∆H negative. Which of the following takes place when the temperature of the reaction vessel is decreased?

A. The gases condense
B. The yield of hydrogen increases
C. The concentration of the reactants remain constant
D. More of the hydrogen iodide decomposes
E. The yield of hydrogen iodide increases

Question 19:

• WAEC 1991

2NaNO₃ → 2NaNO₂ + O₂. From the equation above, what is the volume of oxygen produced at s.t.p. when 8.5g of 2NaNO₃ is heated until no further gas is evolved? (2NaNO₃ = 85, molar volume of gases at s.t.p. = 22.4dm³)

A. 1.12dm³
B. 2.24dm³
C. 4.48dm³
D. 11.2dm³
E. 22.4dm³

Question 20:

• WAEC 1991

Esterification of propane 1,2,3-triol and unsaturated higher carboxylic acids will produce

A. Fats
B. Soap
C. Methly-propanoate
D. Alkanols
E. Oils