Question

a) A chem 1314 student named richard B. Lee needed 12.8 ml of .112 M NaOH to titrat 15.0 ml of an unknown H2SO4 solution what is the molarity of the unknown acid?

Answer 1

The balanced equation is

2 NaOH + H₂SO₄ ------> Na₂SO₄ + 2 H₂O

Number of moles of NaOH = molarity * volume of solution in L

Number of moles of NaOH = 0.112 * 0.0128 L = 0.00143 mole

From the balanced equation we can say that

2 mole of NaOH requires 1 mole of H2SO4 so

0.00143 mole of NaOH will require

= 0.00143 mole of NaOH *(1 mole of H2SO4 / 2 mole of NaOH)

= 0.000715 mole of H2SO4

Moalrity of H2SO4 = number of moles of H2SO4 / volume of solution in L

Molarity of H2SO4 = 0.000715 / 0.015 L = 0.0477 M

Therefore, molarity of unknown acid = 0.0477 M