Chemistry - Complete s-block Question with Solution | TestHub

Lithium sulfate ($L{i}_{2}S{O}_4$) on strong heating decomposes to lithium oxide ($L{i}_{2}O$) and sulfur trioxide ($S{O}_3$). Sulfur trioxide is an acidic gas that reacts with lime water ($Ca(OH{)}_2$) to form calcium sulfite ($CaS{O}_3$), which is insoluble and causes turbidity (the lime water test). Other alkali metal sulfates are thermally stable and do not decompose under normal heating conditions.

The decomposition reaction is:

$$L{i}_{2}S{O}_4(s)\stackrel{\Delta }{\to }L{i}_{2}O(s)+S{O}_3(g)$$

The lime water test reaction is:

$$S{O}_3(g)+Ca(OH{)}_2(aq)\to CaS{O}_3(s)+H_{2}O(l)$$