Question

Which of the following statements is true for all the alkali metals?

• A. Their nitrates decomposes on heating to give the corresponding nitrites and oxygen
• B. Their chlorides are deliquescent and crystallize as hydrates.
• C. They react with water to form hydroxide and hydrogen.
• D. They react with halogens to form only ionic halides $M^{+}{X}^{-}$ .

Answer 1

Answer: (C)

$\left(\text{A}\right)4{\left(\text{LiNO}\right)}_{\text{3}}\to 2{\left(\text{Li}\right)}_{\text{2}}\text{O}+4{\left(\text{NO}\right)}_{\text{2}}+{\left(\text{O}\right)}_{\text{2}}$

$2{\text{NaNO}}_{\text{3}}\to 2{\text{NaNO}}_{\text{2}}+{\text{O}}_{\text{2}}$ similar decomposition with the nitrates of $\text{K,}\text{Pb}$ and $\text{Cs}$ )

$\left(B\right)$ Only $\text{LiCl}$ is deliquescent and crystallises as a hydrate $\text{LiCl}$ . $2H_{2}O$

$\left(\text{C}\right)2\text{M}+2{\left(\text{H}\right)}_{\text{2}}\text{O}\to 2{\left(\text{M}\right)}^{\text{+}}+2{\left(\text{OH}\right)}^{-}+{\left(\text{H}\right)}_{\text{2}}$ (M is an alkali metal)

$\left(D\right)$ Halides of $\text{Li}$ are covalent in nature.