7.61 The ionization constant of nitrous acid is 4.5 × 10-4. Calculate the pH of 0.04 M sodium nitrite solution and also its degree of hydrolysis.
Ionization constant of nitrous acid =
Concentration of sodium nitrite () = 0.04 M
Degree of hydrolysis can be calculated as;
Sodium nitrite is a salt of sodium hydroxide (strong base) and the weak acid ()
Suppose moles of salt undergoes hydrolysis, then the concentration of-
from here we can calculate the value of ;
Therefore the degree of hydrolysis