Waec Chemistry Past Questions For Year 1993
Question 16
Some precious stones such as ruby and sapphire consist of aluminum oxide coloured by traces of the oxides of
- A. group lV elements
- B. group l metals
- C. transition metals
- D. alkaline earths
- E. the halogens
Question 17
Which of the following pieces of deposited if a current of 10A was passed through a solution of copper(ll) salt for 965 seconds? (1F = 96500 C)
- A. 0.005 mole
- B. 0.025 mole
- C. 0.05 mole
- D. 1.00 mole
- E. 1.05 mole
Question 18
Examples of polymers include the following except
- A. starch
- B. nylon
- C. wool
- D. perspex
- E. glass
Question 19
Which of the following will not affect the degree of hardness in a sample of temporarily hard water?
- A. Addition of washing soda
- B. Adding of soap
- C. Treatment with carbon exchange resin
- D. Filtration
- E. Distillation
Question 20
The component of air that removed when air is bubbled into alkaline pyrogallol solution is
- A. carbon(lV) oxide
- B. oxgyen
- C. water vapour
- D. nitrogen
- E. helium
