The tendency of forming chloride hydrates of alkaline earth metals is in the order of

Step-by-step solution

Halides of alkaline earth metals form hydrate, so they are hygroscopic in nature. Due to this nature, they can be used as water absorbing compound. Mg is smaller than Ca . Hence, Mg ²⁺ ion polarises water molecule easily than the calcium water molecules get attached to Mg ²⁺ as the water of crystallisation. Similarly Sr is smaller than Ba and easily polarises by water molecule. aligned & i.e. MgCl ₂ 6 H ₂ O > CaCl ₂ 6 H ₂ O , & SrCl ₂ 2 H ₂ O > BaCl ₂ 2 H ₂ O aligned Hence, correct order is Mg > Ca and Sr > Ba .