Question

35.0 mL of acid with an unknown concentration is titrated with 24.6 mL of 0.432 M base. What is the concentration of the acid? Assume the acid contributes 1 mole of (H+) ions/mole of acid and the base contributes 1 mole of (OH-) ions/mole of base.

a)3.29 M
b)0.615 M
c)0.304 M

Answer 1

Since we assume both reactants have 1 equivalent of H+ and OH- ions, we can balance the moles out. The acid of concentration x will have (x M)(0.035 L) = 0.035x moles of acid. Meanwhile, for the base: (0.432 M)(0.0246 L) = 0.0106 moles of base. Since these must be equivalent:
0.035x = 0.0106x = 0.304 M