$CHO-(CHOH)_4-CH_2OH \xrightarrow{Br_2/H_2O} P$; $P$ is

If $\left|\begin{array}{cc}1-i & i \\ 1+2 i & -i\end{array}\right|=x+i y$,then $x$ is equal to

Identify the reagent used in the following reaction.
Benzoic acid $\stackrel{\text{Reagent}}{\Delta}$ Benzoyl chloride + Phosphorous oxychloride + Hydrogen chloride

The difference between volume and pressure coefficients of an ideal gas is

Filiform apparatus is a characteristic feature of

With which of the following does hydrogen combine directly?