Chemistry 1991 Waec Past Questions and Answers

Question 6 :

• WAEC 1991

What is the amount (in mole) of sodium trioxocarbonate (IV) in 5.3 g of the compound? (Na₂CO₃ = 106)

A. 0.05
B. 0.10
C. 0.20
D. 0.50
E. 2.00

Question 7 :

• WAEC 1991

Which of the processes represented by the following equations has the greatest positive entropy change?

A. C₆H_3(l) → C₆H _6(g)
B. H₂O _(s) → H₂O_(l)
C. CuO_(s) + H_2(g) → Cu_(s) + H₂
D. Na₂CO_3(s) + nH₂O_(l) →Na ₂CO₃nH₂O_(s)
E. S_(s) → S_(l)

Question 8 :

• WAEC 1991

Which of the following elements can from more than one acidic oxide?

A. Hydrogen
B. Sulphur
C. Carbon
D. Alumium
E. Iron

Question 9 :

• WAEC 1991

CH₂ = CH₂ + H₂SO₄ → CH₃ - CH₂ -OSO₃H. The reaction illustrated by the equation above is an example of

A. Substitution
B. Oxidation
C. Reduction
D. Addition
E. Displacement

Question 10 :

• WAEC 1991

Brass is an alloy of copper and

A. Iron
B. Chromium
C. Zinc
D. Tin
E. Magnesium