A student wishes to determine the Ka of an unknown weak acid, HA, with a molar mass of 140 g \(\text{mol}^{-1}\). The student first accurately weighs 1.400 g of the unknown acid. The HA is dissolved in a little water, transferred to a 100 mL volumetric flask and distilled water added until the line on flask is reached. A pipette is used to transfer 50.00 mL of this solution to an Erlenmeyer flask. The solution in the Erlenmeyer flask is titrated to the endpoint with standard NaOH solution. The untitrated and titrated samples are mixed in a beaker and the pH of the mixture is determined with a pH meter. What must the student now due to determine the Ka of the solution?  

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