Respuesta :

Number of moles ,n = m/Mr
Molarity, C = n/V
So, Comparing two equations we get,
m = Mr * C * V
= 40 * 0.125 * 5
=25g.

here, Mr = molecular mass of NaOH = 40g/mol
C= 0.125 mol/dm3
V= 5 dm3