Question

What is the molar concentration of 35 mL of H2SO4 that neutralizes 25 mL of 0.320M NaOH

Answer 1

V ( H2SO4) = 35 mL / 1000 => 0.035 L

M ( H2SO4) = ?

V ( NaOH ) = 25 mL / 1000 => 0.025 L 

M ( NaOH ) = 0.320 M

number of moles NaOH:

n = M x V

n = 0.025 x 0.320 => 0.008 moles of NaOH

Mole ratio:

2 NaOH + H2SO4 = Na2SO4 + 2 H2O

2 moles NaOH ---------------------- 1 mole H2SO4
0.008 moles moles NaOH ---------- ??

0.008 x 1 / 2 => 0.004 moles of H2SO4 :

Therefore:

M ( H2SO4) = n / V

M = 0.004 /  0.035

= 0.114 M

hope this helps!