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    • Thread Starter

    okay so i have these two questions for my chem hwk and i just want to check with someone that ive worked it out correctly
    calculate the ph of the following buffer solution:
    12.2g of benzoic acid and 7.20g of sodium benzoate in a 250cm3 aqueous solution
    Ka for benzoic acid is (6.30x10^-5)

    so firstly i worked out the moles of each of them and got:
    benzoic acid = 0.1 moles
    sodium benzoate = 0.05 moles

    from that i then calculated concentrations getting:
    benzoic acid= 0.4
    sodium benzoate = 0.2

    i then plugged this into the equation of [H+] = Ka x [products]/[reactants]
    and got an answer of pH 4.5 ((after doin the -log thing)

    is this correct???
    •  Official Rep

     Official Rep
    Sorry you've not had any responses about this. Are you sure you've posted in the right place? Here's a link to our subject forum which should help get you more responses if you post there.

    Just quoting in Amusing Elk so she can move the thread if needed :wizard:
    (Original post by Amusing Elk)
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