Calculate the pH of a 0.120 M solution of NaNO2?

Question

Calculate the pH of a 0.120 M solution of NaNO2

HINT: find Kb from Ka of the conjugate acid

Answer 1

You'll probably in your book have a table that has the Ka for HNO2. You can calculate Kb if you remember the KaKb=1X10^-14.

Kb=[HNO3][OH-]/[NO2-]

Both terms in the numerator will be equal, and let them equal x. You can probably get by with letting [NO2-] = 0.120, though quite properly, it should be 0.120-x. Solve for x, and use the expression for Kw to calculate [H+] and finally pH.

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