What is the concentration of a H2SO4 solution if 10.0 mL of the solution is neutralized by

Question

7.8 mL of a 0.20 M NaOH solution?

Answer 1

7.8 mL of 0.20M NaOH contains 0.0078*0.20 = 0.00156 mole of NaOH
But
H2SO4+2NaOH = Na2SO4 + 2H2O
So 0.00156 mole of NaOH will neutralize 0.00156/2=0.00078 mole of H2SO4 contained in 10mL.
So concentration of H2SO4 = 0.00078/0.0100
= 0.078M