Water - Jamb Chemistry Past Questions and Answers

Question 21:

• JAMB 1989

Calcium hydroxide is added in the treatment of town water supply to

A. Kill bacteria in the water
B. Facilitate coagulation of organic particles
C. Facilitate sedimentation
D. Improve the taste of the water

Question 22:

• JAMB 1989

A hydrated salt of formula MSO₄.xH₂ O CONTAINS 45.3% by mass of water of crystalisation. Calculate the value of x [M = 56, S = 32, O = 16, H = 1 ]

A. 3
B. 5
C. 7
D. 10

Question 23:

• JAMB 1989

Mortar is NOT used for under-water construction because

A. It hardens by lose of water
B. Its hardening doe not depend upon evaporation
C. It requires concrete to harden
D. It will be washed away by the flow of water

Question 24:

• JAMB 1990

A blue solid, T, which weighed 5.0g was placed on a table. After 8 hours, the resulting pink solid was found to weigh 5.5g. It can be inferred that substance T?

A. Is deliquescent
B. Is hydroscopic
C. Has some molecules of water of crystallization
D. Is efflorescent

Question 25:

• JAMB 1991

A sample of temporary hard water can be prepared in the laboratory by?

A. Disolving calcium chloride in distilled water
B. Saturating lime water with carbon (IV) oxide
C. Saturating distilled water with calcium hydroxide
D. Dissolving sodium hydrogen trioxocarbonate (IV) in some distilled water