What is the pH of a solution that results from diluting 0.50mol formic acid (HCO2H) and 0.10 mol sodium formate (NaHCO2) with water to a volume of 1.0 L? (Ka of HCO2H = 1.8 x 10^-4)

This comes from the definition of Ka:



where the numbers in brackets, [] are concentrations (moles/liter)

(equation 1)





Enter those into equation 1, above, and solve for . The pH is defined as:

(equation 2)

so, once you have found the hydrogen ion concentration (equation 1), calculate the pH from equation 2.