The ionisation constant of acetic acid is 1.74 x10-5. calculate the degree of dissociation of acetic acid in its 0.05M solution. calculate the concentration of acetate ion in the solution and its pH.

Solution

$Acetic space space acid space being space straight a space weak space acid comma space Ostwald apostrophe straight s space dilution space law space is space applicable straight alpha space equals square root of straight K subscript straight alpha over straight c end root space equals square root of fraction numerator 1.74 space straight x 10 to the power of negative 5 end exponent over denominator 0.05 end fraction end root space equals 0.0186 left square bracket Ac to the power of minus right square bracket space equals square root of straight c straight K subscript straight a space equals square root of 0.05 straight x 1.74 straight x 10 to the power of negative 5 end exponent end root space equals 9.3 space straight x 10 to the power of negative 4 end exponent space straight M equals 0.00093 space straight M left square bracket straight H to the power of plus right square bracket space equals left square bracket Ac to the power of minus right square bracket space equals 9.3 space straight x 10 to the power of negative 4 end exponent space straight M pH equals negative log left square bracket straight H to the power of plus right square bracket space equals negative log 9.3 straight x 10 to the power of negative 1 end exponent equals 3.03$