Question

Choose the correct statement:

i) Normality and molarity of HCl are same.

ii) Molality and molarity are independent of temperature.

iii) Normality of 1M ${KMnO}_4$ in acidic medium is 5 N.

• A. All are correct
• B. Only ii wrong
• C. Only iii correct
• D. All are wrong

Answer 1

Answer: (B)

Only ii wrong

We have Normailty = molarity$\times$ n-factor

for HCl, we have n-factor = 1

so, normality = molarity
Molarity is dependent on temperature due to temperature factor. However, molality is independent of temperature. Therefore, the statement (ii) is incorrect.

In acidic medium, $KMn{O}_4\to M{n}^{2+}$

so, n-factor = 5

hence, normailty = molarity$\times$ n-factor

hence, normality of 1 M $KMn{O}_4$ = 5N