Jamb Chemistry 1984 Past Questions and Answers

Question 11:

• JAMB 1984

In which of the following reactions does hydrogen peroxide act as a reducing agent?

A. H₂S + H₂O₂ \(\to\) S + 2H₂O
B. PbSO₃ + H₂O₂ \(\to\) PbSO₄ + H₂O
C. 2I+ 2H⁺ + H₂O₂ \(\to\) I₂ + 2H₂O
D. PbO₂ + 2HNO₃ + H₂O₂ \(\to\) Pb(NO₃)₂ + 2H₂O + O₂
E. SO₂ + H₂O₂ \(\to\) H₂SO₄

Question 12:

• JAMB 1984

For the reaction 2Fe³⁺ 2I^- \(\to\) 2Fe²⁺ + I₂, which of the following statements is TRUE?

A. Fe is oxidized to Fe³⁺
B. Fe³⁺ is oxidized to Fe²⁺
C. I^- is oxidized to I₂
D. I^- is reduced to I₂
E. I^- is displacing an electron from Fe³⁺

Question 13:

• JAMB 1984

In dilute solution the heat of the reaction NaOH + HCl = NaCl + H2O is - 57.3kJ. Therefore the heat of the reaction 2NaOH + H₂SO₄ \(\to\) Na₂SO₄ + 2H₂O is

A. + 28.65 kJ
B. - 28.65KJ
C. + 57.3KJ
D. - 114.6 KJ
E. - 229.2 KJ

Question 14:

• JAMB 1984

Which of the following methods may be used to prepare trioxonitrate (V) acid (nitric acid) in the laboratory?

A. Heating ammonia gas with tetraoxosulphate (VI) acid
B. Heating ammonium trioxonitrate (V) with tetraoxosulphate (VI) acid
C. Heating sodium trioxonitrate (V) with tetraoxosulphate (VI) acid
D. Heating potassium trioxonitrate (V) with calcium hydroxide
E. Heating a mixture of ammonia gas and oxygen.

Question 15:

• JAMB 1984

Lime - water, which is used in the laboratory for the detection of carbon(iv)oxide is an aqueous solution of

A. Ca(OH)₂
B. CaCO₃
C. CaHCO₃
D. CaSO₄
E. N₂CO₃