# Calculate the mass of oxalic acid (H2C2O4.2H2O) needed to prepare 250 ml,1 M aqueous solution of oxalic acid.

Molarity of a given solution is defined as the total number of moles of solute per litre of solution.

$Molarity = \frac{n}{V}$

Here,

M is the molality of the solution

n is the number of moles of the solute

V is the volume of solution given in terms of litres

Molecular weight of oxalic acid (H2C2O4.2H2O) = 126 g/mol.

M = n/V

0.1 M = n/0.25L

n = 0. 025 mol

Number of moles = Given mass/Molar mass

0. 025 mol = m / 126

m = 3.15 g

So, amount of oxalic acid is 3.15 g