Sulphur dioxide

2013 NEET 1 question

1. 1 The p-Block Elements
   Roasting of sulphides gives the gas X as a by-product. This is a colourless gas with choking smell of burnt sulphur and causes great damage to respiratory organs as a result of acid rain. Its aqueous solution is acidic, acts as a reducing agent and its acid has never been isolated. The gas X is:
   A $SO_3$ B $H_2S$ C $SO_2$ D $CO_2$
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