Percent by mass : 4.10⁺³%
Further explanation
The concentration of a solution can be expressed in units such as molarity, normality, mass percent, volume percent etc.
[tex]\tt \%mass=\dfrac{mass~solute}{mass~solution}\times 100\%[/tex]
mass solute= mass of NaOH
mass of NaOH :
[tex]\tt 0.001~mol/L\times 1~L\times 40~g/mol=0.04~g[/tex]
mass solution = 1000 g
% mass :
[tex]\tt \dfrac{0.04}{1000}\times 100=4.10^{-3}\%[/tex]
