Question

Above compounds can be differentiated by which of the following chemical test? (used in decreasing order).

• A. $NaOH,NaHC{O}_3,HCl$
• B. $HCl,NaOH,NaHC{O}_3$
• C. $NaHC{O}_3,NaOH,HCl$
• D. $NaOH,HCl,NaHC{O}_3$

Answer 1

The correct option is C $NaHC{O}_3,NaOH,HCl$

As $m-nitrophenol$ and $m-nitrobenzoic$ $acid$ are acidic in nature.

$m-nitrobenzene$ is a neutral compound.

$m-nitro$ $aniline$ is a basic compound.

Now, as $M-nitrobenzoic$ $acid$ is enough acidic that it can react with $NaHC{O}_3$, but $m-nitro$ $phenol$ does not. $M-nitrophenol$ can react with $NaOH$.

Thus first we add $NaHC{O}_3$, to which $m-nitrobenzoic$ $acid$ react and become soluble.

Then we take the residue and $NaOH$ is added to it. Now $m-nitrophenol$ become soluble as it reacts with $NaOH$ to make salt.

Then the residue is taken which contain $m-nitrobenzene$ and $m-nitro$ $aniline$ .

Then we add acid, $m-nitro$ $aniline$ reacts with acid and become soluble. In residue only $m-nitro$ $benzene$ remains.

Thus the reagent use is in the following order.

$NaHC{O}_3,NaOH,HCl$