Chemistry Past Questions and Answers

A piece of metal (M) is dissolved in nitric acid and the resulting solution is treated with a small quantity of sodium hydroxide to produce a white precipitate (B) which redissolves on the addition of excess alkali. The precipitate (B)when ignited in a crucible produces the oxide of the metal(m). The METAL M is

A Zn
B Cu
C Al
D Au
E Ca

Question 157:

Pick out the correct statement

A Zin heated to redness reacts with steam to give oxygen and zinc oxide
B Zinc heated to redness reacts with steam to give oxygen and hydrogen
C Zinc does not react with hot or cold water
D Zinc reacts with hot water to form zinc oxide and hydrogen
E Zinc reacts very easily with cold water to give zinc oxide and hydrogen

Question 158:

Consider the following exothermic reaction 2SO2(g) + O2(g) = 2SO3 (g) . If the temperature of the reaction is reduced from 800oC to 500oC, and no other change takes place, then

A The reaction rate increases
B Concentration of SO3 decreases
C Concentration of SO3 increases
D SO2 gas becomes unreactive
E O2 gas becomes unreactive

Question 159:

The IUPAC name for

A 2-methylbut-3-ene
B 2-methylbut-4-ene
C 3-methylbut-2-ene
D 3-methylbut-1-ene
E 3-methylpent-1-ene

Question 160:

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