Question

(i)Potassium carbonate cannot be prepared by Solvay's process.

(ii)Solution of sodium carbonate is alkaline.

(iii)Beryllium and magnesium do not impart colour to flame.

Answer 1

(i) Potassium carbonate cannot be prepared by Solvay process because potassium bicarbonate being more soluble than sodium bicarbonate does not get precipitated when CO₂ is passed through a concentrated solution of KCl saturated with NH₃

(ii) Sodium carbonate in aqueous solution gets hydrolyzed to give OH- ions ans therefore, gives alkaline tests.
CO₃^2- + H₂O $\to$ HCO₃^- + OH^-

(iii) Beryllium and magnesium do not give any characteristic flame colours because Be and Mg are comparatively smaller and their ionisation energies are very high. Hence, the energy of the flame is not sufficient to excite electrons to higher energy levels. These elements, therefore, do not give any colour in Bunsen flame.