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CAIE IGCSE Chemistry Acid and Base Proton Transfer

CAIE IGCSE Chemistry Acid and Base Proton Transfer
Cambridge IGCSE Chemistry 0620 syllabus for exams in 2026, 2027 and 20282026–2028

Practise defining acids and bases through proton transfer and completing equations that show donation to water or proton acceptance by ammonia-like bases.

How this is tested

  • define an acid as a proton donor and identify the species that transfers H⁺
  • define a base as a proton acceptor and identify the species that receives H⁺
  • complete proton-transfer equations with the correct conjugate ion and charge

Question 6(c)(i)

[Maximum number: 1]

Ethanol is manufactured by two methods:
method 1 fermentation of aqueous glucose
method 2 catalytic addition of steam to an alkene.

The catalyst in method 2 is phosphoric acid, H3PO4\mathrm{H}_{3} \mathrm{PO}_{4}. Dilute phosphoric acid is a weak acid which contains phosphate ions, PO43−\mathrm{PO}_{4}{ }^{3-}.

State what is meant by the term acid.