Answer
$CHCl_2COOH$ is the stronger acid due to the presence of an additional chlorine.
Work Step by Step
Since chlorine is a very electronegative element, its presence in the carbon chain shifts electron density toward the R group, making the O-H bond more polar, and consequently, the hydrogen will be donated more easily.
$CHCl_2COOH$ has more chlorines in the chain than $CH_2ClCOOH$; therefore, it is a stronger acid.
