Chemistry
Give reasons for the following:
(a) Sodium hydrogen sulphate is not an acid, but it dissolves in water to give hydrogen ions according to the equation
NaHSO4 ⇌ H+ + Na+ + SO42-
(b) Anhydrous calcium chloride is used in a desiccator.
Answer
(a) Sodium hydrogen sulphate [NaHSO4] is not an acid but due to the partial replacement of the replaceable hydrogen ion in a dibasic acid [H2SO4] releases a [H+] ion. Thus, we get the above equation.
Therefore, on dissolving in water, it gives hydrogen ions.
(b) Desiccating agents are used to absorb moisture. Anhydrous calcium chloride (CaCl2) has the capacity to absorb moisture as it is hygroscopic hence used as a desiccating agent.
Related Questions
Answer the questions below:
(a) What name is given to the water in the compound copper sulphate-5-water?
(b) If copper sulphate-5-water is heated, anhydrous copper sulphate is formed. What is it's colour?
(c) By what means, other than heating, could you dehydrate copper sulphate-5-water and obtain anhydrous copper sulphate?
(d) Name a deliquescent salt.
(e) Why does hydrated copper sulphate turn white on heating?
State your observation when the following are exposed to the atmosphere:
(a) Washing soda crystals
(b) Iron (III) chloride salts.
Explain clearly how conc. H2SO4 is used as a dehydrating as well as a drying agent.
Distinguish between drying and dehydrating agent.