Molar mass of potassium hydroxide, \(\mathrm{KOH}=(39+16+1) \mathrm{gmol}^{-1}\) \(=56 \mathrm{gmol}^{-1}\)
mole of \(\mathrm{KOH}=0.38 \mathrm{~g} / 56 \mathrm{gmol}^{-1}\) \(=0.0067857 \mathrm{~mol}\)
volume of solution \(=100 \mathrm{~cm}^3\)
\(=\left(\frac{100}{1000}\right) \mathrm{dm}^3=0.1 \mathrm{dm}^3\)
concentration \(\left(\right.\) in mold \(\left.\mathrm{dm}^{-3}\right)=\frac{\text { mole }}{\text { volume }\left(\mathrm{dm}^3\right)}\)
\(=\frac{0.0067875 \mathrm{~mol}}{0.1 \mathrm{dm}^3}\)
\(=0.067857 \mathrm{moldm}^{-3}\)
\(=0.07 \mathrm{moldm}^{-3}\)