Question

0.45 g of a dibasic acid is completely neutralised with 100 ml N/10 NaOH.The molecular weight of acid is ?

Answer 1

Dibasic acid: H₂X, for example H₂SO₄, H₂S, H₂CO₃
H₂X + 2NaOH ---> Na₂X + 2H₂O
1 mol    2 mol           1 mol     2 mol
N/10 (?)   NaOH  =  0.1 mol/L ?
If so, it 100 ml NaOH 0.1 mol/L contains 0.01 mol NaOH and is neutralised with n = 0.5 * 0.01 = 0.005 mol acid.
And so the molar mass of acid:
M = m / n = 0.45 / 0.005 = 90 g/mol

 

Answer 2

Answer:

Explanation:

Dibasic acid: H₂X, for example H₂SO₄, H₂S, H₂CO₃

H₂X + 2NaOH ---> Na₂X + 2H₂O

1 mol 2 mol 1 mol 2 mol

N/10 (?) NaOH = 0.1 mol/L ?

If so, it 100 ml NaOH 0.1 mol/L contains 0.01 mol NaOH and is neutralised with n = 0.5 * 0.01 = 0.005 mol acid.

And so the molar mass of acid:

M = m / n = 0.45 / 0.005 = 90 g/mol