A volume of 10cm3 of sulfuric acid of unknown concentration neutralized 25cm3 of sodium hydroxide solution of concentration 0.4 mol dm-3. The concentration of the acid is: 0.1 mol dm-3

0.25 mol dm-3

0.4 mol dm-3

0.5 mol dm-3

0.5 mol dm⁻³

Explanation:

The reaction that takes place is:

First we convert the given volumes to dm³(1000cm³ = 1 dm³):

Now we calculate how many NaOH moles reacted, using the given volume and concentration:

Then we convert NaOH moles into H₂SO₄ moles, using the stoichiometric coefficients:

Finally we calculate the concentration of H₂SO₄: