1
MCQ (Single Correct Answer)

AIPMT 2015

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
2
MCQ (Single Correct Answer)

AIPMT 2014

Acidity of diprotic acids in aqueous solutions increases in the order
A
H2S < H2Se < H2Te
B
H2Se < H2S < H2Te
C
H2Te < H2S < H2Se
D
H2Se < H2Te < H2S

Explanation

As the atomic size increases down the group the bond length increases and the bond strength decreases and the cleavage of E - H bond become easier thus, more will be the acidity. Thus, order of acidity will be

H2S $$<$$ H2Se $$<$$ H2Te
3
MCQ (Single Correct Answer)

NEET 2013 (Karnataka)

Identify the incorrect statement, regarding the molecule XeO4 :
A
XeO4 molecule is square planar.
B
There are four p$$\pi $$ - d$$\pi $$ bonds.
C
There are four sp3 - p, $$\sigma $$ bonds.
D
XeO4 molecule is tetrahedral.

Explanation

4
MCQ (Single Correct Answer)

NEET 2013

Which of the following does not give oxygen on heating?
A
K2Cr2O7
B
(NH4)2Cr2O7
C
KClO3
D
Zn(ClO3)2

Explanation

(NH4)2Cr2O7 $$\buildrel \Delta \over \longrightarrow $$ N2 + Cr2O3 + 4H2O

Zn(ClO3)2 $$\buildrel \Delta \over \longrightarrow $$ ZnCl2 + 3O2

KClO3 $$\buildrel \Delta \over \longrightarrow $$ KCl + $${3 \over 2}$$O2

2K2Cr2O7 $$\buildrel \Delta \over \longrightarrow $$ 2K2CrO4 + Cr2O3 + $${3 \over 2}$$ O2

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