To find the percentage of sulphur in the organic compound, we need to calculate the amount of sulphur present in the compound. This can be done by converting the given weight of barium sulphate to the weight of sulphur.

1. Calculate the molar mass of barium sulphate:
- Barium (Ba) has a molar mass of 137.33 g/mol.
- Sulphur (S) has a molar mass of 32.06 g/mol.
- Oxygen (O) has a molar mass of 16.00 g/mol.

Therefore, the molar mass of barium sulphate (BaSO₄) is:
(1 * 137.33 g/mol) + (1 * 32.06 g/mol) + (4 * 16.00 g/mol) = 233.38 g/mol

2. Calculate the number of moles of barium sulphate:
The given weight of barium sulphate is 0.4813 g.
Using the molar mass of barium sulphate, we can calculate the number of moles:
Moles = Mass / Molar mass
Moles = 0.4813 g / 233.38 g/mol
Moles ≈ 0.002063 mol

3. Calculate the number of moles of sulphur in barium sulphate:
From the balanced chemical equation of the reaction, we know that one mole of barium sulphate (BaSO₄) contains one mole of sulphur (S).
Therefore, the number of moles of sulphur in the given weight of barium sulphate is also 0.002063 mol.

4. Calculate the weight of sulphur:
The molar mass of sulphur is 32.06 g/mol.
Weight of sulphur = Moles of sulphur * Molar mass of sulphur
Weight of sulphur = 0.002063 mol * 32.06 g/mol
Weight of sulphur ≈ 0.066 g

5. Calculate the percentage of sulphur in the organic compound:
The given weight of the organic compound is 0.157 g.
Percentage of sulphur = (Weight of sulphur / Weight of organic compound) * 100
Percentage of sulphur = (0.066 g / 0.157 g) * 100
Percentage of sulphur ≈ 42.04%

Therefore, the percentage of sulphur in the organic compound is approximately 42.04%.