Waec Chemistry 1998 Past Questions and Answers

Question 6:

• WAEC 1998

What is the function of sulphur (IV) oxide in the reaction represented by the following equation? SO _2(aq) + 2H₂S_(g) → 3S _(s) + 2H ₂O _(l)

A. Dehydrating agent
B. Oxidising agent
C. Bleaching agent
D. Acid
E. Precipitant

Question 7:

• WAEC 1998

Which of the following will produce oxygen and hydrogen during its electrolysis using platinum electrode?

A. Glucose solution
B. Aqueous copper (ll) tetraoxosulphate (IV)
C. Dilute sodium chloride solution
D. Concentrated hydrochloric acid
E. Dilute copper (ll) chloride solution

Question 8:

• WAEC 1998

What mass of copper would be deposited by a current of 1. 0 ampere passing for 965 seconds through copper (ll) tetraoxosulphate (IV) solution? [Cu = 63.5; 1F = 96500C]

A. 0.318g
B. 0.635g
C. 18g
D. 6.35g
E. 9.65g

Question 9:

• WAEC 1998

How many electrons are removed from Cr^2- when it is oxidized to CrO₄^2-?

A. O
B. 2
C. 4
D. 8
E. 10

Question 10:

• WAEC 1998

Substances which absorb water from the atmosphere without dissolving in it are sid to be

A. Anhydrous
B. Hygroscopic
C. Insolube
D. Hydrated
E. Efflorescent