A substance 'X' when heated with `conc.H_2SO_4` liberates a gas which turns starch paper blue. The substance 'X' is

Kl when heated with conc . H_2SO_4 , it forms

Oxalic acid when heated with conc. H_2 SO_4 it gives out

A solution of a sodium salt gives yellow precipitate with both Pb^(2+) and Ag^(+) ions. Moreover, the acidified solution of sodium salt with KNO_(2) liberates a coloured gas which turns starch paper blue. The anion is :

Greenish yellow gas which turns starch iodide paper black.

Formic acid when heated with conc . H_2 SO_4 produces …….. .

When aluminium is heated with conc. H_(2)SO_(4)

Name the gas that turns moist starch iodide paper blue black.

Name the gas that turns moist starch iodide paper blue black.

A white solid imparts a violet colour to a Bunsen flame. On being heated with concentrated H_(2)SO_(4) , the solid gives violet vapours that turn starch paper blue. The salt may be :

Why sugar turns black when added to conc. H_2SO_4 ?