Question

Hydrogenation of benzoyl chloride in the presence of $Pd$ and $BaS{O_4}$ followed by treatment with formaldehyde and $50\%$ $KOH$ gives

Answer 1

Use the Rosenmund reduction reaction in the presence of Rosenmund catalyst. In this hydrogenation process, benzoyl chloride will be reduced. And gives a new carbon functional group product.

Complete step by step answer:
According to the question, Firstly look at chemical reactions
Rosenmund reduction- It is a hydrogenation process in which acid chloride reduces and produces aldehyde. This reaction is catalyzed by palladium on barium sulfate, it is also called Rosenmund catalyst.
Hydrogenation- When a chemical reaction occurs between hydrogen molecules and other elements in the presence of catalysts like palladium, platinum, and nickel are called Hydrogenation reactions.
Catalyst- It is the type of substance that increases the rate of the reaction without participating in the reaction.
Now, let see the reaction
given
benzoyl chloride - ${C_6}{H_5}COCl$
palladium - $Pd$
barium sulfate - $BaS{O_4}$
${C_6}{H_5}COCl + {H_2}\xrightarrow{{Pd/BaS{O_4}}}{C_6}{H_5}CHO + HCl$
After the reaction we got
${C_6}{H_5}CHO$ - Benzaldehyde
$HCl$ - Hydrochloric acid
Now, let what will happen when Benzaldehyde react with formaldehyde in the presence of $50\% KOH$
${C_6}{H_5}CHO + C{H_2}O\xrightarrow{{50\% KOH}}{C_6}{H_5}C{H_2}OH$
Here, we got Benzyl alcohol.
This reaction is called the Cannizaro reaction.
Cannizaro reaction- In this reaction when the molecule of aldehyde gives alcohol and carboxylic acid. It comes in the news for $1853$. Its name is based upon the name of Stanislao Cannizzaro who was an Italian chemist.

Note:
Rosenmund reduction reaction name based upon the name of German chemist Karl Wilhelm Rosenmund at $1918$. The activity of Palladium is reduced by the Barium Sulfate to prevent over reduction. Because Barium Sulfate has a low surface area.