During a titration experiment, a 150.0 mL solution of 0.05 M sulfuric acid (H2SO4) is neutralized by 300.0 mL solution with an unknown concentration of sodium hydroxide (NaOH).

Question

What is the concentration of the sodium hydroxide solution?

The answer I got is, 0.25 M

Answer 1

the acid is diprotic (two H+ per molecule)

so it's like 150.0 mL of 0.10 M H+

it takes twice as much NaOH (300.0 mL) to neutralize

so the concentration is half ... 0.05 M ... same as the original acid