Calculate the pH of a solution that is 0.322 M in nitrous acid (HNO₂)and 0.178 M in potassium nitrite (KNO₂). The acid dissociation constant of nitrous acid is 4.50 × 10^-4. A)3.093 B)3.607 C)14.26 D)10.91 E)4.589

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The correct answer is A because the pH of a solution can be calculated using the Henderson-Hasselbalch equation: pH = pKa + log([A-]/[HA]), where pKa is the acid dissociation constant, [A-] is the concentration of the conjugate base, and [HA] is the concentration of the acid. In this case, the pKa of nitrous acid is 4.50 × 10^-4, the concentration of the conjugate base (nitrite ion) is 0.178 M, and the concentration of the acid (nitrous acid) is 0.322 M. Plugging these values into the equation, we get: pH = 4.50 × 10^-4 + log(0.178/0.322) = 3.093.

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