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IB Chemistry HL 3.1.3 Amphiprotic species Question Bank

Practise IB Chemistry HL 3.1.3 by applying amphiprotic species to exam-style questions.

Syllabus
First assessment 2025
Course
Chemistry HL
Level
HL

Exam points

  • identify the relevant chemical structure, process or evidence
  • apply the correct chemical model or equation
  • evaluate the result using chemical reasoning and data

3.1.3—Amphiprotic species question 1

[Maximum number: 2]

Phosphine (IUPAC name phosphane) is a hydride of phosphorus, with the formula PH3\mathrm{PH}_{3}.

Phosphine is usually prepared by heating white phosphorus, one of the allotropes of phosphorus, with concentrated aqueous sodium hydroxide. The equation for the reaction is:

P4( s)+3OH−(aq)+3H2O(l)→PH3( g)+3H2PO2−(aq)\mathrm{P}_{4}(\mathrm{~s})+3 \mathrm{OH}^{-}(\mathrm{aq})+3 \mathrm{H}_{2} \mathrm{O}(\mathrm{l}) \rightarrow \mathrm{PH}_{3}(\mathrm{~g})+3 \mathrm{H}_{2} \mathrm{PO}_{2}^{-}(\mathrm{aq})

The ion H2PO2−\mathrm{H}_{2} \mathrm{PO}_{2}^{-}is amphiprotic. Outline what is meant by amphiprotic, giving the formulas of both species it is converted to when it behaves in this manner.

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