A-LevelChemistryChemical bondingOct/Nov 2021Paper 1 Q71 Mark
The strength of hydrogen bonding increases as the electronegativity of the element bonded to hydrogen increases. Some information for a range of hydrides is given. hydride | boiling point /K ---|--- PH3 | 185 HCl | 188 HF | 293 H2O | 373 Which statement and reason about these hydrides is correct?
AThe boiling point of PH3 is much lower than the boiling point of H2O because PH3 does not form hydrogen bonds or instantaneous dipole-induced dipole forces between its molecules.
BThe boiling point of HF is higher than the boiling point of HCl because the bond energy of H-F is greater than the bond energy of H–Cl.
CThe boiling point of H2O is higher than the boiling point of HF because each hydrogen bond between the H2O molecules is stronger than each hydrogen bond between HF molecules.
DThe boiling points of PH3 and HCl are similar because the molecules of PH3 and HCl have the same number of electrons and similar intermolecular forces.
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The correct answer is D. This question tests the candidate's understanding of chemical bonding within the Chemistrysyllabus. The examiner's mark scheme requires...
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