Question

In a titration 20cm3 of 1.0M HCI reacted with 25cm3 of NaOH. What was the concentration of sodium hydroxide ? In a titration 20cm3 of 1.0M HCI reacted with 25cm3 of NaOH. What was the concentration of sodium hydroxide ? @Chemistry

Answer 1

It's not unreasonable to assume the mass densities of both solutions are very similar, since they will be dominated by the mass density of water.

The reaction is HCl + NaOH = NaCl + H2O, which means the reactants are in a 1:1 relationship. That being the case, the ratio of the volumes must be the reciprocal of the ratio of the molarities:

V_acid/V_base = M_acid/M_base.

Because the moles that react must be equal:

moles_acid = M_acid V_acid = moles_base = M_base V_base.

A little algebra transforms that equation to the one above.

Putting in your numbers, I find M_base = 0.80 M.