Question

Why does sulphur on reacting with concentrated nitric acid gives sulphuric acid instead of sulphur dioxide?

• A. It has greater reactivity with acid.
• B. End valency for oxidation 6.
• C. End valency for oxidation 4.
• D. All of the above

Answer 1

Answer: (B)

End valency for oxidation 6.

Concentrated nitric acid acts as an oxidizing agent for both sulfur & carbon. In the case of sulfur, $S$ will get the oxygen atoms & the water needed for the reaction: $S+6HNO3\to H_{2}S{O}_4+2H_{2}O+6N{O}_2$ so if sulfur is converted to $S{O}_2$ first, it will proceed into $S{O}_3$ & eventually to $H_{2}S{O}_4$.