WAEC Chemistry Past Questions & Answers - Page 33

161.

Which of the following reactions are always exothermic? 1. Neutralization Il. Decomposition III. Combustion

A.

I and II only

B.

I and III only

C.

II and IIl only

D.

I, II and III

Correct answer is B

  • LIST OF EXOTHERMIC REACTIONS
  • any combustion reaction.
  • a neutralization reaction.
  • rusting of iron (rust steel wool with vinegar)
  • the thermit reaction.
  • reaction between water and calcium chloride.
  • reaction between sodium sulfite and bleach (dilute sodium hypochlorite)
  • reaction between potassium permanganate and glycerol.

162.

Which of the following statements is correet for a reaction at equilibrium?

A.

All reactions cease to occur

B.

The eaction has gone to completion

C.

The rates of the forward and backward reactions are equal

D.

The amount of product equals the amount of reactants

Correct answer is C

In a chemical reaction, chemical equilibrium is the state in which the forward reaction rate and the reverse reaction rate are equal. The result of this equilibrium is that the concentrations of the reactants and the products do not change.

163.

Which of the following substances is not a reducing agent?

A.

C

B.

CO

C.

O\(_2\)

D.

H\(_2\)

Correct answer is C

- A reducing agent is oxidized, because it loses electrons in the redox reaction. - Elemental oxygen is a strong oxidizing agent.

164.

Which of the following compounds would release hydrogen when reacted with sodium metal? 

I. CH\(_3\)COOH

II. CH\(_3\)CH\(_2\)OH

III. CH\(_3\)COOCH\(_3\)

A.

I only

B.

I and II only

C.

Il and IIl only

D.

I and Ill only

Correct answer is B

No explanation has been provided for this answer.

165.

An alkanol containing 60% carbon by mass would have a molecular formula [H=1.0. C-12.0, O= 16.0]

A.

CH\(_3\)OH

B.

C\(_2\)H\(_5\)OH

C.

C\(_3\)H\(_7\)OH

D.

C\(_4\)H\(_9\)OH

Correct answer is C

No explanation has been provided for this answer.