Question

The boiling point of Sb is greater than Bi.
A.True
B.False

Answer 1

Hint: The size of element increases as we move down the group. Sb and Bi belong to the same group. The variation of boiling point occurs in lower elements of a group due to inert pair effect.

Complete step by step solution:
The element with chemical symbol Sb is antimony and the element Bi is bismuth.
They belong to group number 15 of the periodic table. The elements included in group number 15 are nitrogen, phosphorus, arsenic, antimony and bismuth.
While moving down the group the atomic size of the element increases because an extra shell is added as the number of periods increases. The shielding effect also increases down the group because of the increase in number of inner electrons. Hence the size of bismuth is greater than the size of antimony.
No doubt boiling point increases with increase in size, but there is another effect that is the same into existence as we move down the group. The effect is inert pair effect; it states that as we move down the group the participation of s orbital decreases. Inert pair effect is weaker from nitrogen till arsenic, but it is maximum in case of Bi and hence the electrons in s orbital remain unbounded and the melting point or boiling point decreases because of decrease in interaction. So the boiling point of Sb is greater than Bi.

So the answer is option A

Note: Boiling point is the point when the liquid state exists in the equilibrium with the vapor state. It is a point when the vapor pressure becomes equal to the external pressure. It is constant at constant point at external pressure.