Which of the following compounds is formed when sodium burns in excess supply of air?

Among the following,the incorrect statement is

The basicity of the hydroxides of the following alkali metals is of the order:

Given below are two statements:
Statement $I$: The chlorides of $Be$ and $Al$ have $Cl^{-}$-bridged structure. Both are soluble in organic solvents and act as Lewis acids.
Statement $II$: Hydroxides of $Be$ and $Al$ dissolve in excess alkali to give beryllate and aluminate ions.
In the light of the above statements,choose the correct answer from the options given below.

Nitrates of all the metals are

Which of the following does not liberate a brown gas?