Question

Polarization power of cation increases when:
A. Charge on the cation increases.
B. Size of the cation increases.
C. Charge on the cation decreases.
D. Both charge and size of the cation increase.

Answer 1

First of all, read the question carefully. After getting some idea on Polarization power of cation, we can understand the condition in which case does it increase. Polarization power is based on Fajan's rule.

Complete step by step answer: Polarization power of a cation can be defined as the ability of cation to distort an anion. The tendency of anion to become polarized by the cation is called its polarizability. Polarization power of cation depends on charge and radius. Charge/radius is proportional to polarization power of cation. If charge on the cation increases, polarization power of cation increases because they are directly proportional to each other. If radius of cation increases, polarization power of cation decreases because they are inversely proportional to each other. By comparing the answer to the above given options, option A, charge on the cation is the correct answer. Remaining options are wrong because size does not increase and charge does not decrease with increase of polarization power of cation.
So, the correct answer is “Option A”.

Additional Information: The polarization power of cation increases, more is the distortion of anion.

Note: The polarization power of cation and polarizability improves the covalent bond with some favourable conditions. They are small cation, large anion, and large charges are the conditions that can help polarization power of cation. Polarization power is an extract from Fajan’s rules. Generally, based on fajan's rules, compounds are likely to be ionic, if there is a small positive charge on the cation, the cation is said to be large and anion is said to be small.