Chemistry Past Questions and Answers

The normal boiling point of a liquid is defined as

A The temperature at which its vapour pressure equals the atmospheric pressure
B The temperature at which bubbles begin to form
C The temperature at which the vapour pressure equals 1 temperature
D The temperature at which the rate of condensation of vapour equals the rate of vaporisation of the liquid
E The temperature at which the space above the liquid is saturated

Question 92:

Which of the following compounds will form a solution if exposed to air?

A Na2CO3.10H2O
B NaNO3
C CuSO4
D CaCl2
E Na2SO4.10H2O

Question 93:

The most common type of chemical reaction which alkanes undergo is

A Substitution
B Addition
C Condensation
D Polymerisation
E Double decomposition

Question 94:

Consider the following exothermic reaction 2SO2(g) + O2(g) â†” 2SO3(g) If the temperature of the reaction is reduced from 800°C to 500°C, an 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 O3 gas becomes unreactive

Question 95:

If excess zinc is added to a bluish green solution of copper (II) sulphate, and the excess zinc filtered off after completion of reaction, a colourless solution is obtained because

A Both zinc and copper are metals
B The sulphate radical and the zinc ion are divalent
C Zinc is more electropositive than copper
D Both zinc and copper form depositive ions in solution
E Zinc is a reducing agent