Assertion . The mobility of sodium ion is lower than that of potassium ion . Reason . The ionic mobilities depend upon the effective radius of the ion .

Assertion . The mobility of sodium ion is lower than that of potassium

1.	Assertion . The mobility of sodium ion is lower than that of potassium ion . Reason . The ionic mobilities depend upon the effective radius of the ion .
Answer» If both assertion and reason are true, and reason is the true explanation of the assertion. If both assertion and reason are true, but reason is not the true explanation of the assertion. If assertion is true, but reason is false If both assertion and reason are false. Solution :Correct explanation . Because of smaller size , the extent of hydration of `NA^(+)` ions is HIGHER than that of `K^(+)` ions . As a result , effective radius and hence the mass of HYDRATED `Na^(+)` ions is higher than that of `K^(+)` ions and , therefore , their mobility is LOWER than that of `K^(+)` ions .