Water - Jamb Chemistry Past Questions and Answers

Question 1:

• JAMB 2019

A sample of hard water contains some calcium sulphate and calcium hydrogen carbonate. The total hardness may therefore be removed by

A. Boiling the water
B. Adding excess calcium hydroxide
C. Adding a calculated amount of calcium hydroxide
D. Adding sodium carbonate
E. Adding magnesium hydroxide

Question 2:

• JAMB 2019

In which of the following are water molecules in the most disorderly arrangement?

A. Ice at -10°C
B. Ice at 0°C
C. Water at 100°C
D. Steam at 100°C

Question 3:

• JAMB 2019

The method that can be used to convert hard water to soft water is

A. Chlorination
B. Passage over activated charcoal
C. The use of an ion-exchange resin
D. Aeration

Question 4:

• JAMB 1978

A sample of hard water contains some calcium sulphate and calcium hydrogen carbonate. The total hardness may therefore be removed by

A. Boiling the water
B. Adding excess calcium hydroxide
C. Adding a calculated amount of calcium hydroxide
D. Adding sodium carbonate
E. Adding magnesium hydroxide

Question 5:

• JAMB 1978

A gas jar was inverted over burning yellow phosphorus floating over water in a beaker. After burning, the water level was found to rise in the gas jar. The water level rises because

A. Pressure inside the gas jar is greater than pressure outside it
B. The air in the gas jar had been used up by burning
C. Oxygen in the gas jar had been used up by burning
D. Nitrogen in the gas jar had been used up by burning
E. The temperature in the jar had risen considerably