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

Options

A. Their nitrates decomposes on heating to give the corresponding nitrites and oxygen.
B. Their chlorides crystallise as hydrates
C. They react with water to form hydroxide and hydrogen
D. They readily react with halogens to form ionic halides, `M^(+)X^(-)`.

Answer

3

Explanation

`(1)4LiNO_(2)rarr2Li_(2)O+4NO_(2)+O_(2)`
`2NaNO_(3)rarr2NaNO_(2)+O_(2)(` similar decomposition with the nitrates of `K,Rb` and `Cs)`
`(2)` Only `LiCl` is deliquescent and crystallises as a hydrate `LiCl.2H_(2)O`
`(3) 2M+2H_(2)Orarr2M^(+)+2OH^(-)+H_(2)(M=` an alkali metal )
`(4)` Halides of `Li` are covalent in nature.