tj asked in Science & MathematicsChemistry · 1 decade ago

how to prepare a buffer solution?

The preparation of 1 L 0.1M phosphate buffer, pH= 6.7 starting with 1M H3P04 and 1 M NaOH, pKa = 7.2 .... help!


please show me the solution.. thanks a lot

1 Answer

  • 1 decade ago
    Favorite Answer

    Since you have 1 M H3PO4 and you want a final concentration of 0.1 M, you need to dilute the H3PO4 by 10 fold. So, take 100 mls of the

    1 M H3PO4 and add about 800 mls of water. Then adjust the pH to 6.7 with the 1 M NaOH, and finally, bring the final volume to 1000 mls. If you want to do it by calculations, you can use the Henderson Hasselbalch equation as follows:

    pH = pKa + log [salt]/[acid] and plug in the appropriate values.

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