A 0.1 molar solution of nitrous acid is 7.1 percent ionised at equilibrium what is the

A. Concentration Hydrogen ion and ph
B. Ka value of nitrous acid

2 answers

A. The concentration of hydrogen ion in a 0.1 molar solution of nitrous acid is 7.1 x 10^-3 moles/L and the pH is 2.15.

B. The Ka value of nitrous acid is 7.1 x 10^-4.
A is right.
B is incorrect.
See your other post for the correct values for A, B, C.