JAMB Chemistry 1980 Question 9

Question 9

Chemical Formulae and Equations

Which one of the following reactions is correct as written?

A.FeCl₂ + 3NH₄OH → Fe(OH)₃ + 3NH₄Cl.
B.Pb₂O₃ + 4HCl → PbCl₂ + 2H₂O.
C.PbNO₃ + H₂S → PbS + 2HNO₃
D.NaOH + H₂SO₄ → NaHSO₄ + H₂O.
E.2NH₄NO₃ → N₂ + 2H₂O.

Show the answer and explanation

Answer: D (NaOH + H₂SO₄ → NaHSO₄ + H₂O.)

Explanation

Only D has correct formulae and balances (1 Na, 3 H, 1 S, 5 O on each side). The others have wrong formulae or do not balance, e.g. FeCl₂ would give Fe(OH)₂.