Question

For,$C{H_3}C{H_2}CON{H_2}\xrightarrow[{B{r_2}}]{{NaOH}}$ A, Aqueous solution of A.
A.Turns blue litmus to red
B.turns red litmus to blue
C.does not affect the litmus
D.decolorize the litmus

Answer 1

In chemistry, acid, base nature of any chemical substance identified by litmus paper, methyl orange, and phenolphthalein. These are the basic indicators. Litmus paper is one of the popular indicators that turns blue to red in case of acid while red to blue in the base.

Complete step by step answer:
Chemical reactions occur in the presence of many circumstances. So, they named according to their behavior of reactant and product.
Here, we have
$C{H_3}C{H_2}CON{H_2}$- amide
$NaOH$- sodium hydroxide
$B{r_2}$ - bromine
When amide reacts in the presence of $NaOH$ and $B{r_2}$ reagents and gives ${1^o}$ amine. This reaction is known as Hofmann rearrangement. It is also known as Hofmann degradation, its name based on the name of August Wilhelm von Hofmann.
In this reaction, reagents form sodium hypobromite that will transform into primary amide then into isocyanate. Then isocyanate is hydrolyzed to a primary amine and also gives carbon dioxide.
$C{H_3}C{H_2}CON{H_2}\xrightarrow[{B{r_2}}]{{NaOH}}C{H_3}C{H_2}N{H_2}$
Now, we got ethylamine or amine that is base. And we know that base turns red to blue. Therefore, option B is the correct answer here.
This reaction used to convert Nicotinic acid to 3-Aminopyridine also.
So, option B is the correct answer here.

Note: Methyl orange - It is another indicator to identify the acid and base nature of the chemical substance. Its natural color is orange, it shows red in acid and yellow in the base. Phenolphthalein - natural color of this indicator is colorless, it shows colorless in acid means no change and pink in the base.