(a(i))[1]
Give a chemical equation for the reaction in stage 1.
(a(ii))[4]
State the conditions needed for stage 2, and write the chemical equation for the reaction.
(a(iii))[1]
Give the chemical equation for the reaction in stage 3.
(a(iv))[1]
Identify the substance that reacts with oleum in stage 4.
(b(i))[2]
Finish the dot-and-cross diagram to show the electron arrangement in one molecule of hydrogen sulfide. Display only the outer-shell electrons.
(b(ii))[1]
Use balancing by inspection for the reaction of hydrogen sulfide with sulfur dioxide below. $\ldots\ldots \text{H}_2\text{S} + \text{SO}_2 \rightarrow \ldots\ldots \text{S} + \ldots\ldots \text{H}_2\text{O}$