Question

Potassium carbonate cannot be made by the Solvay process because
A. potassium hydrogen carbonate is unstable
B. potassium hydrogen carbonate is rather too soluble in water to be precipitated
C. potassium carbonate is insoluble in water
D. potassium carbonate is soluble in water

Answer 1

Correct Answer - B
Unlike `NaHCO_(3)` which is sparingly soluble in water, `KHCO_(3)` is fairly soluble in water. Thus, when `CO_(2)` is passed through ammoniated brine, `NaHCO_(3)` gets precipitated, while `KHCO_(3)` does not get precipitated when `CO_(2)` is passed through an ammoniacal solution of KCl. However, it can be made by passing `CO_(2)` into a solution of potassium hydroxide. Evaporation and subsequent ingnition gives the corbonate:
`overset(+)(K)overset(-)(O)H(aq.)+CO_(2)(g)toK^(+)HCO_(3)^(-)(aq.)`
`2K^(+)HCO_(3)^(-)(aq.)to(K^(+))_(2)CO_(3)^(2-)(s)+H_(2)O(l)+CO_(2)(g)`.