Separation of mixtures and purification of chemical substances - Jamb Chemistry Past Questions and Answers

Question 16:

• JAMB 1980

In an attempt to remove sugar from a breaker containing a quantity of sand and sugar, 2 M ammonium chloride solution was accidentally added instead of water. Which of the following method could be used to remove the ammonium chloride from the mixture?

A. Fractional distillation
B. Crystallization
C. Filtration followed by evaporation
D. Evaporation followed by sublimation
E. Filtration followed by sublimation

Question 17:

• JAMB 1980

In an attempt to remove sugar from a breaker containing a quantity of sand and sugar, 2 M ammonium chloride solution was accidentally added instead of water. Which of the following method could be used to remove the ammonium chloride from the mixture?

A. Fractional distillation
B. Crystallization
C. Filtration followed by evaporation
D. Evaporation followed by sublimation
E. Filtration followed by sublimation

Question 18:

• JAMB 1981

When a bottle of Coca-Cola is opened, bubbles of evolve. The gas is?

A. Hydrogen
B. Carbon monoxide
C. Carbon dioxide
D. Sulphur oxide
E. Chlorine

Question 19:

• JAMB 1981

When glowing splint is inserted into the mouth of a jar containing a gas, the splint is extinguished. The gas gives a white precipitate when passing into barium hydroxide. The gas is?

A. Methane
B. Hydrogen chloride
C. Hydrogen
D. Nitrogen
E. Carbondioxide

Question 20:

• JAMB 1981

The following compounds are given with their corresponding boiling points.
Compound Boiling Point
i.................................14°C
ii................................24°C
iii................................0°C
iv................................120°C
V.................................-2°C
From the above information, indicate which of the following is correct?

A. All the compounds are gaseous at 20 °C
B. One of the compounds is gaseous at 20 °C
C. Two of the compounds are gaseous at 20 °C
D. Three of the compounds are gaseous at 20 °C
E. None of the compounds is gaseous at 20 °C