Waec Chemistry 2000 Past Questions and Answers

Question 36:

• WAEC 2000

Two-organic substances are labelled K and L if K gave a blue-black colour with iodine solution and L gave a deep red precipitate with Million's reagent, it can be concluded that

A. K is a carbhydrate and L is a protein
B. K is alkaline and L is acidic
C. K is unsaturated and L is a reducing sugar
D. K is a reducing agent and L is an amino acid

Question 37:

• WAEC 2000

A colourless, odourless liquid T, gives effervesce with sodium trioxocarbonate (IV) and a white precipitate with silver trioxonitrate (V) solution T is mose probably

A. Sodium chloride soluttion
B. Barium chloride solution
C. Dilute trioxonitrate (V) acid
D. Dilute hydroxide is unstable

Question 38:

• WAEC 2000

When sodium hydroxide solution is added to a solution of zinc salt, the white precipitate fromed redissolves in excess sodium hydroxide because

A. Sodium is more reactive than zinc
B. Sodium hydroxide is a strong alkali
C. Zinc hydroxide is amphoteric
D. Zinc hydroxide is unstable

Question 39:

• WAEC 2000

Which of the following on burning in air contributes to acid rain?

A. Sulphur
B. Magnesium
C. Aluminium
D. Zinc

Question 40:

• WAEC 2000

If 20 cm³ of distilled water is added to 80 cm³ of 0.50 mol dm^-3 hydrochloric acid, the concentration of the acid will change to

A. 20 mol dm^-3
B. 0.40 mol dm^-3
C. 2.00 mol dm^-3
D. 5.00 mol dm ^-3