Solution

Silica gel is known to adsorb $$H_2O_2$$. Anhydrous $$CaCl_2$$ absorbs $$H_2O$$ and is usually known to exist in hydrous form. Gas masks work on chemical adsorption. It has activated carbon sites that selectively pick gases like $$H_{2}S$$ and $$NH_{3}$$. Zeolites are shape selective catalysts .They are used to adsorb compounds of $$Mg $$ and $$Ca$$ . Thus, they are used as water softners