Chemistry 2018 Waec Past Questions and Answers

Question 16 :

• WAEC 2018

At what temperature does the solubility of \(KNO_{3}\) equal that of \(NaNO_{3}\)?

A. 0°C
B. 20°C
C. 30°C
D. 40°C

Question 17 :

• WAEC 2018

When a salt is added to its saturated solution, the salt

A. Dissolves and the solution becomes super saturated
B. Dissolves and the solution becomes unsaturated
C. Precipitates and the solution remains unchanged
D. Dissolves and crystals are formed

Question 18 :

• WAEC 2018

When substance X was added to a solution of bromine water, the solution became colourless. X is likely to be

A. Propane
B. Propanoic acid
C. Propyne
D. Propanol

Question 19 :

• WAEC 2018

The preferential discharge of ions during electrolysis is influenced by the

A. Mechanism of electrolysis
B. Electrolytic reactions
C. Nature of the electrode
D. Type of electrolytic cell

Question 20 :

• WAEC 2018

The valence electrons of \(_{12}Mg\) are in the

A. 3s orbital
B. 2p\(_{x}\)
C. 2s orbital
D. 1s orbital