Oxidation of organic compound A with ${\mathrm{Na}}_2{\mathrm{Cr}}_2{\mathrm{O}}_7\text{ and }{\mathrm{H}}_2{\mathrm{SO}}_4$ gives compound B, which on reduction with H₂ in the presence of Ni catalyst gives ethyl alcohol. Give the name of compound A.

Given data : It is given to identify  the name of compound A, from the given options.

Explanation 

A is a compound which is ethyl alcohol ($C{H}_{3}C{H}_{2}OH$) we have to oxidize sodium dichromate($N{a}_{2}C{r}_2{O}_7$) and Sulfuric acid then we will get Acetic acid ($C{H}_{3}COOH$) then we have to reduce it will Hydrogen($H_2$) or Nickel ($Ni$) then we will get ($C{H}_{3}C{H}_{2}OH$)

The chemical reaction is as follows. 

$C{H}_{3}C{H}_{2}OH\underset{H_{2}S{O}_4}{\overset{N{a}_{2}C{r}_2{O}_7}{\to }} C{H}_{3}COOH \underset{Ni}{\overset{H_2}{\to }}C{H}_{3}C{H}_{2}OH$

Hence, the correct option (B). Ethanol.