The relationship between Normality ($N$) and Molarity ($M$) is given by the equation: $N = M \times n\text{-factor}$ For Sodium Carbonate ($Na_2CO_3$), the salt dissociates into ions as: $Na_2CO_3 \rightarrow 2Na^+ + CO_3^{2-}$. The total positive charge (or total negative charge) exchanged is 2. Therefore, the n-factor (valency factor) is 2. Given that the Normality ($N$) is 0.2 N, we can calculate the Molarity ($M$): $0.2 = M \times 2$ $M = \frac{0.2}{2} = 0.1 \text{ M}$