Reference no: EM131703672

Could someone please check my work

1. A standardized solution of sodium hydroxide at 0.239 M was used to titrate an unknown acid comprising 3 acid hydrogen ions. Knowing that 32.4 mL of base were required to reach the end point with a sample of 1.95 g of acid, calculate the molar mass of the acid.

H3A + 3NaOH = Na3A + 3H2O

1 mol  3 mol      1 mol    3 mol

Number of moles of NaOH = .0324 L x .239 M = .00774 mol/L

Molar Ratio: 1:3

Number of moles of H3A = .00774 mol x 1/3 = .00258 mol

Molar mass of H3A = 1.95 g / .00258 mol = 755.8 g/mol

The molar mass of the acid is 756 g/mol (3 significant numbers)