JAMB Chemistry 1979 Question 30

Calcium hydroxide and ammonium chloride when heated together will give an important product. This compound may be obtained dry by

1. A.dissolving it in water, recrystallizing it, and then drying in the oven
2. B.passing it through a concentrated aqueous solution of sodium hydroxide
3. C.passing it through concentrated sulphuric acid
4. D.passing it through calcium oxide
5. E.passing it through anhydrous calcium chloride.