Q: (a) LiCl is hydrated, but NaCl is always anhydrous. Why ?
(b) Why is it that although Li+ is far smaller than the other metals ions, it moves through a solution less rapidly than the others ?
Solution: (a) Li+ is smaller in size and hence it is more hydrated than Na+ which has a larger size.
(b) Smaller the size of cation, larger the charge, then greater the hydration. The dense charge of Li+ attracts several layers of water molecules around it. They increase the effective size of the ion, thus slowing it down.