pH and pOH of an acetic acid solution (8401)

F_y_Q — 2025-02-17T05:12:03Z

Calculate the pH and pOH of a 0.001 mol/L acetic acid solution, given its ionization constant

From the ionization constant value, you can calculate the concentration of ions at equilibrium:

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The acidity constant follows the equation:

The equilibrium concentrations, based on the initial concentration, are as follows:

Substitute these concentrations into the equilibrium constant equation to get:

You can do one of two things: solve the quadratic equation or assume that, given the small value of the constant, the denominator is very close to one. Here's how to do each.

Solving the quadratic equation:

You get the value . The other value obtained is negative and lacks chemical significance.

Approximating the denominator as one:

Since the acid concentration is low, it's not a good idea to use the approximation, and it is preferable to solve the quadratic equation to avoid an error of over .

Taking the first calculated dissociation degree value, you can calculate the equilibrium hydronium concentration:

The pH calculation is straightforward:

You can calculate the pOH considering their relationship:

EjerciciosFyQ

pH and pOH of an acetic acid solution (8401)