Write a balanced equation for each reaction, keeping them in the correct order. Where needed, use $\rightleftharpoons$ to show that the reaction is at equilibrium.
Give three distinct operating conditions used in the second stage.
State one large-scale application of sulfuric acid.
Most of the sulfur used in the Contact process is recovered from sulfur compounds found in crude oil and natural gas by the Claus process. In this process, about one third of the hydrogen sulfide, $\text{H}_2\text{S}$, present in the oil or gas, is changed into sulfur dioxide, $\text{SO}_2$. Balance the equation for this reaction: $\ldots\text{H}_2\text{S} + \ldots\text{O}_2 \rightarrow \ldots\text{SO}_2 + \ldots\text{H}_2\text{O}$.
The $\text{SO}_2$ formed is then reacted catalytically with the remaining $\text{H}_2\text{S}$, producing sulfur and water. $2\text{H}_2\text{S} + \text{SO}_2 \rightarrow 3\text{S} + 2\text{H}_2\text{O}$ What are the oxidation numbers of the sulfur-containing substances in this reaction? $\text{H}_2\text{S}$, $\text{SO}_2$, $\text{S}$ Which substance is reduced? Explain your answer.
Outline, with equations, how acid rain is produced from the exhaust gases of motor vehicles.
State one environmental effect of acid rain.
Sulfur dioxide is used to preserve dried fruits and vegetables. What chemical property of $\text{SO}_2$ makes it suitable as a food preservative?