Question

What is the concentration of the base (KOH) in the following titration, given the data below?

0.75 M HBr Unknown KOH
initial burette reading

0.0 ml


0.5 ml


final burette reading

22.6 ml




37.5 ml

Answer 1

HBr and KOH, molarity is equal to normality. Substituting the known values,

(0.75 M) x (22.6 mL - 0 mL) = Nb x (37.5 mL - 0.5 mL)

Nb = 0.46 N

Mb = 0.46 M

Answer 2

To calculate the concentration of the base based on the titration, the concept used is the equal of number of equivalence of the acid used to that of the base. From this,
Na x Va = Nb x Vb
For HBr and KOH, molarity is equal to normality. Substituting the known values,
(0.75 M) x (22.6 mL - 0 mL) = Nb x (37.5 mL - 0.5 mL)
Nb = 0.46 N
Mb = 0.46 M
Thus, the concentration of the base is approximately 0.46 M.