1
MCQ (Single Correct Answer)

AIPMT 2010 Prelims

Which one of the following molecular hydrides acts as a Lewis acid?
A
NH3
B
H2O
C
B2H6
D
CH4

Explanation

Among the given molecules, only diborane(B2H6) is electron deficient i.e., it does not complete octet.

Thus, it acts as a Lewis acid.

NH3 and H2O being electron rich species behave as Lewis base.
2
MCQ (Single Correct Answer)

AIPMT 2009

Among the following which is the strongest oxidising agent?
A
Br2
B
I2
C
Cl2
D
F2

Explanation

Standard reduction potential of halogens are positive and decrease from fluorine to iodine. So, F2 is the strongest oxidizing agent.
3
MCQ (Single Correct Answer)

AIPMT 2009

The straight chain polymer is formed by
A
hydrolysis of CH3SiCl3 followed by condensation polymerisation
B
hydrolysis of (CH3)4Si by addition polymerisation
C
hydrolysis of (CH3)2SiCl2 followed by condensation polymerisation
D
hydrolysis of (CH3)3SiCl followed by condensation polymerisation.

Explanation

Hydrolysis of (CH3)2SiCl2 followed by condensation polymerization.



4
MCQ (Single Correct Answer)

AIPMT 2009

The stability of +1 oxidation state among Al, Ga, In and Tl increases in the sequence
A
Al < Ga < In < Tl
B
Tl < In < Ga < Al
C
In < Tl < Ga < Al
D
Ga < In < Al < Tl

Explanation

The given elements belong to 13th group. The elements mainly exhibit +3 and +1 oxidation states. As we know, the stability of lower oxidation state i.e., +1 state, increases on moving down the group due to inert pair effect. The, stability follows the order :

Al < Ga < In < Tl

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