25.00cm3 of sodium hydroxide was pipetted into a conical flask. It was titrated against 0.10mol/dm3 hydrochloric acid. The mean volume of acid needed was 24.00cm3. Calculate the concentration of sodium hydroxide used in the titration.

First write out the chemical equation:

^{​​​​​​}HCl + NaOH -> NaCl + H₂0

Next construct a table with the information we have and in what units.

Next write out what calculation triangle we need:

Number of moles = vol in dm3 X concentration = 0.0024 mol

One mole of HCl: one mole of NaOH, therefore 0.0024mol of NaOH

Concentration = no of moles / vol in dm3 = 0.096 mol/dm3 to 2dp.