Normality is defined as the number of equivalents of solute per liter of solution. Equivalents are the moles of solute divided by the number of moles of electrons transferred per mole of solute. Since KMnO4 undergoes a five-electron reduction (MnO4- -> Mn2+), 0.1 N KMnO4 has a molarity of:

$$M = N \times \frac{M_{KMnO4}}{5}$$

$$M = 0.1 \ N \times \frac{158.034\ g/mol}{5}$$

$$M = 0.0316\ M$$

Therefore, the molarity of 0.1 N KMnO4 is 0.0316 M.