CAIE A Level Chemistry 9701 · Group 17
The table shows the bond dissociation energies of hydrogen chloride and hydrogen bromide.
| Bond | Bond dissociation energy / kJ mol⁻¹ |
|---|---|
| H–Cl | 431 |
| H–Br | 366 |
(a) Describe the relative reactivities of chlorine and bromine as oxidising agents. Explain this trend. (b) Describe and explain the relative ease with which chlorine and bromine react with hydrogen. (c) Describe the relative thermal stabilities of HCl and HBr and explain this using the data in the table.
7 marks, so the mark scheme is looking for about 7 separate creditworthy points. Making the same point twice in different words earns it once.
Describe means: Say what happens or what something is like, in order and with detail. You are not being asked why. If there is data, quote it: name the trend, then give figures with units at the points where it changes.
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