# Which of the following acids has the smallest dissociation constant

$(a)\;CH_3CHFCOOH \\ (b)\; FCH_2CH_2COOH \\ (c)\; BrCH_2CH_2COOH \\ (d)\; CH_3CHBrCOOH$

The least dissociated constant is for weakest acid
(ie) $BrCH_2CH_2COOH$. $Br$ is less electronegative than $F$ and $Br$ is two carbon atoms away from $-COOH$
Hence c is the correct answer.