Which of the following reagents is not used for the removal of permanent hardness of water?

What is not true about ice?

Which of the following pairs of ions causes hardness in water?

$A$ sample of water containing some dissolved table sugar and common salt is passed through organic ion exchange resins. The resulting water will be

Match the reactants in List-$I$ with the products in List-$II$.

List-$I$	List-$II$
$(a). H_2O + H_2S$	$(i). (H_3O^{+}, HS^{-})$
$(b). H_2O + N^{3-}$	$(ii). (NH_3, OH^{-})$
$(c). H_2O + SiCl_4$	$(iii). (OH^{-}, H_3S^{+})$
$(d). H_2O + F_2$	$(iv). (SiO_2, HCl)$
	$(v). (SiO_4^{4-}, Cl_2)$
	$(vi). (O_2, F^{-})$
	$(vii). (HF, OH^{-})$
	$(viii). (OH^{-}, NH_3)$

Write chemical reactions to show the amphoteric nature of water.