Waec Chemistry 1993 Past Questions and Answers

Question 11:

• WAEC 1993

Sulphur burns in air to form

A. An acidic oxide
B. A basic oxide
C. An amphoteric oxide
D. A neutra oxide
E. A mixed oxide

Question 12:

• WAEC 1993

In which of the following changes is ∆S negative ?

A. H₂O_(l) → H₂O_(s)
B. C_(s) + 1/2O_{2,/sub>[sub](g)} → CO_(g)[/sub]
C. PCI_5(g) → PCl_3(g) + Cl_2(g)
D. NaCl_(s) + aq →Na_+(aq) + Cl_-(aq)
E. NH_3(g) + HCl_(g)

Question 13:

• WAEC 1993

Chlorine is is used in water treatment as

A. A germicide
B. A decolorizing agent
C. An antioxidant
D. A coagulating agent
E. An aerating agent

Question 14:

• WAEC 1993

Which of the following pieces of deposited if a current of 10A was passed through a solution of copper(ll) salt for 965 seconds? (1F = 96500 C)

A. 0.005 mole
B. 0.025 mole
C. 0.05 mole
D. 1.00 mole
E. 1.05 mole

Question 15:

• WAEC 1993

Some precious stones such as ruby and sapphire consist of aluminum oxide coloured by traces of the oxides of

A. Group lV elements
B. Group l metals
C. Transition metals
D. Alkaline earths
E. The halogens