1
MCQ (Single Correct Answer)

AIPMT 2004

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
MCQ (Single Correct Answer)

AIPMT 2004

The molecular formula of diphenyl methane,



How many structural isomers are possible when one of the hydrogen is replaced by a chlorine atom ?
A
6
B
4
C
8
D
7

Explanation

Only four structural isomers are possible for diphenyl methane.

3
MCQ (Single Correct Answer)

AIPMT 2003

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.

The – OH in alcohols is almost neutral.

Acetylene is also weakest acid.

Thus the correct order is

RCOOH > HOH > ROH > HC $$ \equiv $$ CH

depending upon the rate of donation of proton.
4
MCQ (Single Correct Answer)

AIPMT 2003

Name of the compound given below is
A
4-ethyl-3-methyloctane
B
3-methyl-4-ethyloctane
C
2, 3-diethylheptane
D
5-ethyl-6-methyloctane

Explanation

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