The correct decreasing order for acid strength is :-

$\mathrm{NO}_{2} \mathrm{CH}_{2} \mathrm{COOH}>\mathrm{NCCH}_{2} \mathrm{COOH}>$

$\mathrm{FCH}_{2} \mathrm{COOH}>\mathrm{CICH}_{2} \mathrm{COOH}$

$\mathrm{FCH}_{2} \mathrm{COOH}>\mathrm{NCCH}_{2} \mathrm{COOH}>$

$\mathrm{NO}_{2} \mathrm{CHCOOH}>\mathrm{CICH}_{2} \mathrm{COOH}$

$\mathrm{NO}_{2} \mathrm{CH}_{2} \mathrm{COOH}>\mathrm{FCH}_{2} \mathrm{COOH}>$

$\mathrm{CNCH}_{2} \mathrm{COOH}>\mathrm{CICH}_{2} \mathrm{COOH}$

$\mathrm{CNCH}_{2} \mathrm{COOH}>\mathrm{O}_{2} \mathrm{NCH}_{2} \mathrm{COOH}>$

$\mathrm{FCH}_{2} \mathrm{COOH}>\mathrm{CICH}_{2} \mathrm{COOH}$