Hi Kavya,

We know that  Na2SO4 +BaCl2 = 2NaCl + BaSO4. Molar mass of Na2SO4 is 142g/mol,  BaSO4 is 233.3g/mol BaCl2 is 208.3 g/mol.

Number of sulphate ions = number of moles in barium ion in BaSO4.

Number of moles in 10 gram of Barium sulphate= number of moles of Barium sulphate equals to 10/233.40 which is 0.0428 moles. Therefore number of moles of sulphate ions is 0.0428 moles. Number of moles of sulphate Ion equal to number of moles of sodium sulphate that is molarity × volume.

5×V = 0.0428

V= 8.57×0.001 litre

V= 8.57 ml

I hope you got the answer.

All the best!