1
AIPMT 2015
MCQ (Single Correct Answer)
+4
-1
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
2
AIPMT 2015
MCQ (Single Correct Answer)
+4
-1
The variation of the boiling points of the hydrogen halides is in the order HF > HI > HBr > HCl.

What explains the higher boiling point of hydrogen fluoride?
A
There is strong hydrogen bonding between HF molecules.
B
The bond energy of HF molecules is greater than in other hydrogen halides.
C
The effect of nuclear shielding is much reduced in fluorine which polarises the HF molecule.
D
The electronegativity of fluorine is much higher than for other elements in the group.
3
AIPMT 2015
MCQ (Single Correct Answer)
+4
-1
Strong reducing behavior of H3PO2 is due to
A
high electron gain enthalpy of phosphorus
B
high oxidation state of phosphorus
C
presence of two $$-$$OH groups and one P$$-$$H bond
D
presence of one $$-$$OH group and two P$$-$$H bonds.
4
AIPMT 2015
MCQ (Single Correct Answer)
+4
-1
The formation of the oxide ion, O2$$-$$(g) from oxygen atom requires first an exthermic and then an endothermic step as shown below:
O(g) + e$$-$$ $$ \to $$ O$$-$$(g);  $$\Delta $$fHo = $$-$$141 kJ mol$$-$$1

O$$-$$(g) + e$$-$$ $$ \to $$ O2$$-$$(g);  $$\Delta $$fHo = +780 kJ mol$$-$$1

Thus, process of formation of O2$$-$$ is isoelectronic with neon. It is due to the fact that,
A
O$$-$$ ion has comparatively smaller size than oxygen atom
B
oxygen is more electronegative
C
addition of electron in oxygen results in larger size of the ion
D
electron repulsion outweighs the stability gained by achieving noble gas configuration.
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