Waec Chemistry Past Questions For Year 1992
Question 21
Which of the following gases will have the highest rate of diffusion under the same conditions? (H = 1, C =12, O = 16, S = 32, CI = 35.5)
- A. O2
- B. CI2
- C. HCI
- D. H2S
- E. CO2
Question 22
When sucrose is warmed with Fehling's solution
- A. a silver mirror is produced
- B. the solution turns milky
- C. a brick-red precipitate is formed
- D. there is no precipitate
- E. a blue coloration is produced
Question 23
The following salts are readily soluble in water except
- A. Na2CO3
- B. Pb(NO3)2
- C. KCI
- D. CuCO3
- E. PbSO4
Question 24
If a reaction is said to be exothermic, which of the following statements is a correct deduction from the information?
- A. the reaction vessel gets hotter as the reaction proceeds
- B. ∆H for the reaction is positive
- C. the rate of the reaction increases with time
- D. the activation energy of the reaction is high
- E. the rate of the reaction increases with time
Question 25
Vulcanization of rubber
- A. stops the growth of fungus on the rubber
- B. increases the solubility of the rubber
- C. decreases the elasticity of the rubber
- D. hardnes the rubber through cross-linkage
- E. removes sulphur from the rubber
