25cm^3 of HCl of concentration 1mol/dm3 reacts with 20cm NaOH. Calculate concentration of NaOH.

Convert to cm3 to dm3: HCl = 25/1000 = 0.025 NaOH = 20/1000 = 0.020 amount(mol) = concentration x volume 0.025 x 1 = 0.025 concentration = amount solute(mol)/amount NaOH(mol concentration = 0.025/0.020 concentration = 1.25