Kerala KEAM 5 June 2024 Solved Paper

We are given the following information:- Normality (N) = 0.02 N- Volume of solution = 50 mL = 0.050 L- Molar mass of oxalic acid = 126 g/molWe know that normality $N$ is related to molarity $M$ by the equation:$$N = n \times M$$where $n$ is the number of equivalents per mole. For oxalic acid (H$_2$C$_2$O$_4$), the number of replaceable hydrogen ions $n$ is 2, because each molecule of oxalic acid can donate two protons (H$^+$) in a reaction.Therefore, the molarity of the oxalic acid solution is:$$M = \frac{N}{n} = \frac{0.02}{2} = 0.01 \, mol/L$$Now, the amount of substance (in moles) present in 50 mL (0.050 L) of the solution is:$$moles of oxalic acid = M \times Volume = 0.01 \times 0.050 = 0.0005 \, mol$$Finally, to find the mass, we use the molar mass of oxalic acid:$$mass = moles \times molar mass = 0.0005 \times 126 = 0.063 \, g = 63 \, mg$$Thus, the mass of oxalic acid in 50 mL of the solution is $\boxed{63 \, mg}$. Quick Tip: In solutions, normality (N) is used to express the equivalent concentration of a solution. Remember, normality is related to molarity by the number of replaceable ions or equivalents in the solution.