Answer to Question #164483 in General Chemistry for Sabitu Osama

Question

Between I3CCH2CH2COOH and CH3CH2CCI2COOH which one is strong

Answer 1

CH₃CH₂CCl₂COOH is stronger acid than I₃CCH₂CH₂COOH because the closer the electronegative substituent to the carboxylic acid group, the more -I effect of such substituents affects the acid strength. In CH₃CH₂CCl₂COOH two chlorine atoms are at the 2nd carbon atom, while iodine atoms in I₃CCH₂CH₂COOH are too far from the carboxylic acid group to significantly increase the acid strength. Moreover, chlorine itself has greater -I effect compared to iodine.