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Wed 26 Sep, 2012 06:54 pm
Three solutions contain methanoic acid (HCOOH, pKa = 3.75) at a concentration of 0.2 mol/L and sodium methanoate at concentrations of:
(i) 0.1 mol/L
(ii) 0.2 mol/L
(iii) 0.4 mol/L
Calculate the pH of these three solutions
@cicibebe,
Do the same thing I did for acedic acid to figure out the pH of pure methanoic acid solution ([H+]=[HCOO-]). Then put in a [HCOO-] concentration equal to the [NaHCOO] (the salt dissociates completely in aqueous solutions). Calculate the [H+] concentrations and use the definition of pH for the answers.
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