What is the pH of the final solution?

A buffer solution is made by adding 13.45 g of sodium hypochlorite (NaClO) to 345 mL of

0.456 M hypochlorous acid (HClO). What is the pH of the final solution? Assume no

volume change.

1 Answer

Relevance
  • 4 months ago

    HClO <--> H+ + ClO-

    Ka = [H+][ClO-] / [HClO] = 3.0 x 10-8

    (NOTE: I've found several values for this Ka. Use the value in your source.)

    Since this is a buffer, you can certainly use the Henderson- Hasselbalch equation. You can also always use the expression for Ka:

    molarity ClO- = 13.45 g / 74.44 g/mol / 0.344 L = 0.524 M ClO-

    Ka = 3.0X10^-8 = [H+] (0.524) / (0.456)

    [H+] = 2.61X10^-8

    pH = -log (2.61X10^-8) = 7.58

Still have questions? Get answers by asking now.