Dehydration of hydrates of halides of calcium, barium and strontium i.e., ${\mathrm{CaCl}}_{2}·6{\mathrm{H}}_{2}\mathrm{O}$${\mathrm{BaCl}}_{2}·2{\mathrm{H}}_{2}\mathrm{O}$${\mathrm{SrCl}}_{2}·2{\mathrm{H}}_{2}\mathrm{O}$, can be achieved by heating.
These become wet on keeping in air. Which of the following statements is correct about these halides?

1. Act as dehydrating agent

2. Can adsorb moisture from air

3. Tendency to form hydrate decreases from calcium to barium

4. All of the above

Hint: A dehydrating agent is a substance that dries or removes water from a material.

Chlorides of alkaline earth metals are hydrated salts. Due to their hygroscopic nature, they can be used as a dehydrating agent, to adsorb moisture from air.
Extent of hydration decreases from Mg to Ba i.e., ${\mathrm{MgCl}}_{2}·6{\mathrm{H}}_{2}\mathrm{O}$${\mathrm{CaCl}}_{2}·6{\mathrm{H}}_{2}\mathrm{O}$${\mathrm{BaCl}}_{2}·2{\mathrm{H}}_{2}\mathrm{O}$${\mathrm{SrCl}}_{2}·2{\mathrm{H}}_{2}\mathrm{O}$.