which of the following reacts with hot n concentrated h2so4 and also decolourise bromine water 
a)Na2SO3
B)NaHSO4
C)Na2SO4
D)Na2S​

In acidic medium, Na₂SO₃ reacts with reacts with bromine in the following manner:
Na₂SO₃ + Br₂ + H₂O → Na₂SO₄ + 2HBr
​HBr is formed that decolorises teh solution.