Which order is correct when the following compounds are arranged in order of increasing melting point?

A.     \({\text{C}}{{\text{H}}_{\text{4}}} < {{\text{H}}_{\text{2}}}{\text{S}} < {{\text{H}}_{\text{2}}}{\text{O}}\)

B.     \({{\text{H}}_{\text{2}}}{\text{S}} < {{\text{H}}_{\text{2}}}{\text{O}} < {\text{C}}{{\text{H}}_{\text{4}}}\)

C.     \({\text{C}}{{\text{H}}_{\text{4}}} < {{\text{H}}_{\text{2}}}{\text{O}} < {{\text{H}}_{\text{2}}}{\text{S}}\)

D.     \({{\text{H}}_{\text{2}}}{\text{S}} < {\text{C}}{{\text{H}}_{\text{4}}} < {{\text{H}}_{\text{2}}}{\text{O}}\)

A

One respondent stated that it would be best to write from least reactive to most reactive in both of these questions. However, “increasing” is written in bold in both questions and, also, this type of question has been asked extensively on previous papers and hence candidates would have understood what was asked for explicitly if they had looked at some of the previous examination papers. In the case of Q.13 60% of candidates gave the correct answer and in Q.27, 68% had the question correct.