Question

Calculate the mass of oxalic acid dihydrate (H2C2O4.2H2O) required to prepare 0.1M 250ml of its aqueous solution.?​

Answer 1

Answer:-

3.15g

Explanation :-

• Molar mass of Hydrogen = 1g/mol

• Molar mass of Carbon = 12g/mol

• Molar mass of Oxygen = 16g/mol

Hence, molar mass of H₂C₂O₄.2H₂O :-

= [1×2]+[12×2]+[16×4]+[2×18]

= 2+24+64+36

= 126g/mol

Let the required mass of Oxalic acid dihydrate be 'x' grams.

Number of mole in 'x' grams :-

= Given Mass/Molar mass

= x/126 mole

Now, let's convert the volume of solution from mL to L.

=> 1mL = 0.001L

=> 250mL = 250(0.001)

=> 0.25L

Molarity of a solution :-

= Moles of solute/Liters of solution

=> [x/126]/0.25 = 0.1

=> x/[126×0.25] = 0.1

=> x/31.5 = 0.1

=> x = 31.5(0.1)

=> x = 3.15g

Thus, the required mass of Oxalic acid dihydrate [H₂C₂O₄.2H₂O] is 3.15g.