Waec Chemistry 1993 Past Questions and Answers

Question 31:

• WAEC 1993

The product of the reaction between ethanol and excess acidified K_{2[sub]Cr[sub]2}O₂ is
[/sub][/sub]

A. Ethanal
B. Ethylethanoate
C. Ethanoic acid
D. Ethyne
E. Ethanedioic acid

Question 32:

• WAEC 1993

When ammonium chloride is dissolved in water in a test tube, the tube feels colder showing that

A. The solution is unsaturated
B. Sublimation has ocurred
C. Ammonia gas is evolved
D. The process is endothermic
E. Condensation has occurred

Question 33:

• WAEC 1993

Zinc displaces copper from an aqueous solution of copper (ll) salt because

A. Copper is a transition element
B. Copper is a moderately reactive metal
C. Zinc and copper have reducing prperties
D. Zinc is more reactive than copper
E. Zinc reacts with both acids and alkalis

Question 34:

• WAEC 1993

The alloy used for metal work and plumbing contains

A. Lead and tin
B. Iron and carbon
C. Copper and tin
D. Aluminium and copper
E. Lead and antimony

Question 35:

• WAEC 1993

Classify each of the following as physical change or a chemical change:
(a) fractional distillation of liquefied air;
(b) cracking of petroleum fractions;
(c) conversion of rhombic sulphur to monoclinic sulphur;
(d) chromatographic separation of chlorophyll.