What is obtained when glycerol is heated with oxalic acid at $110\,^{\circ}C$?

If we use pyrene $(CCl_4)$ in the Riemer-Tiemann reaction in place of chloroform,the product formed is

When alkyl cyanides are hydrolysed to the corresponding carboxylic acids,the gas evolved is:

Which one of the following functional groups undergoes hydrolysis with alkali to yield an acid group?

Find product $V$ in the following reaction sequence:
$CH_3-CH(CH_3)-COOH$ $\xrightarrow[H_3O^{+}]{LiAlH_4} I$ $\xrightarrow{PBr_3} II$ $\xrightarrow[ether]{Mg} III$ $\xrightarrow{CO_2} IV$ $\xrightarrow{H_3O^{+}} V$

Identify the product $X$ in the following reaction.
$CH_3COCl \xrightarrow{H_2O} X$