The $$-$$ OH group of an alcohol or the $$-$$ COOH group of a carboxylic acid can be replaced by $$-$$ Cl using
A
phosphorus pentachloride
B
hypochlorous acid
C
chlorine
D
hydrochloric acid
Explanation
ROH + PCl5 $$ \to $$ RCl + POCl3
+ HCl
RCOOH + PCl5 $$ \to $$ RCOCl + POCl3
+ HCl
2
AIPMT 2003
MCQ (Single Correct Answer)
Which one of the following orders of acid strength is correct ?
A
RCOOH > ROH > HOH > HC $$ \equiv $$ CH
B
RCOOH > HOH > ROH > HC $$ \equiv $$ CH
C
RCOOH > HOH > HC $$ \equiv $$ CH > ROH
D
RCOOH > HC $$ \equiv $$ CH > HOH > ROH
Explanation
Carboxylic acid is much stronger than water
and alcohol. Since the carboxylate ion after the
removal of proton is stabilised by resonating
structures as higher is the tendency to donate
proton, stronger is the acid.
