For Nitrous Acid,HNO₂,K_a = 4 $\times$ 10^-4

Multiple Choice

For nitrous acid,HNO₂,K_a = 4.0 $\times$ 10^-4.Calculate the pH of 0.27 M HNO₂.

A) 1.98
B) 0.57
C) 3.97
D) 12.02
E) none of these