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Q.
The correct order of acidic strength of the carboxylic acid is
Aldehydes Ketones and Carboxylic Acids
Solution:
Acidic strength order
Because the $S . O$ of $C B'$ is
As, the acidic strength order $1>2>4>3$.
So, $BrCH _{2} CH _{2} CO _{2} H$ is weakest acid and hence it has smallest value of dissociation constant.