P - Block Elements MCQ Questions & Answers in Inorganic Chemistry | Chemistry
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641.
The variation of the boiling point of the hydrogen halides is in the order $$HF > HI > HBr > HCl.$$ What explains the higher boiling point of hydrogen fluoride?
A
The electronegativity of fluorine is much higher than for other elements in the group
B
There is strong hydrogen bonding between $$HF$$ molecules
C
The bond energy of $$HF$$ molecules is greater than in other hydrogen halides
D
The effect of nuclear shielding is much reduced in fluorine which polarises the $$HF$$ molecule
Answer :
There is strong hydrogen bonding between $$HF$$ molecules
Since, there is a strong hydrogen bonding between $$HF$$ molecules. Hence, boiling point is highest for $$HF.$$
$$HF > HI > HBr > HI$$
642.
The reddish brown coloured gas formed when nitric oxide is oxidised by air is
643.
Match the uses of the metal aluminium given in column I with its properties given in column II and mark the appropriate choice.
Column I
Column II
a.
Transmission cables
1.
High malleability
b.
Aircraft body
2.
High electrical conductivity
c.
Packing industry
3.
High thermal conductivity
d.
Utensile
4.
Light and tough alloys
A
a - 2, b - 1, c - 3, d - 4
B
a - 4, b - 3, c - 2, d - 1
C
a - 2, b - 4, c - 1, d - 3
D
a - 3, b - 4, c - 1, d - 2
Answer :
a - 2, b - 4, c - 1, d - 3
No explanation is given for this question. Let's discuss the answer together.
644.
Which one of the following properties is not shown by NO?
A
It is diamagnetic in gaseous state
B
It is neutral oxide
C
It combines with oxygen to form nitrogen dioxide
D
It’s bond order is 2.5
Answer :
It is diamagnetic in gaseous state
Nitric oxide is paramagnetic in the gaseous state because of the presence of one unpaired electron in its outermost shell.
The electronic configuration of $$NO$$ is
$$\sigma _{1s}^2\sigma _{1s}^{ * 2}\sigma _{2s}^2\sigma _{2s}^{ * 2}\sigma _{2{p_z}}^2\pi _{2{p_x}}^2 = \pi _{2{p_y}}^2\pi _{2{p_x}}^{ * 1}$$