C9: Acids, Bases, Neutralisation, Salts and Titrations
Official Cambridge & Imperial ESAT specification requirements for Acids, Bases, Neutralisation, Salts and Titrations on the Chemistry paper. Understand the syllabus boundaries, spot distractor traps engineered by examiners, and master the 2-step Sub-90 shortcuts that compress solve time well below the 88.8-second cutoff.
Official Syllabus Subtopics
Requirements specified in the UAT-UK framework
- 1Logarithmic pH scale: [H⁺] changes by factor of 10 for each 1 unit change in pH
- 2Strong acids (complete dissociation) vs weak acids (partial dissociation equilibrium)
- 3Neutralisation reaction: H⁺(aq) + OH⁻(aq) ⟶ H₂O(l)
- 4Acid reactions with metals (⟶ salt + H₂), metal oxides/hydroxides (⟶ salt + H₂O), carbonates (⟶ salt + H₂O + CO₂)
- 5Preparation of soluble and insoluble salts (precipitation reactions)
- 6Acid-base volumetric titrations and back-titrations
Sub-90 Exam Speed Tips
How top candidates solve this spec under the 88.8s clock
Diluting a strong acid by a factor of 10 increases its pH by exactly 1 unit; diluting by 100 increases pH by 2.
Diprotic acids (e.g. H₂SO₄) require 2 moles of NaOH per mole of acid for complete neutralisation.
Examiners engineer distractor options using common algebraic expansions and sign slips. Always test structural ratios or invariants before calculating arithmetic values.
Tested Topics in Specification C9
Master the individual question patterns and Sub-90 shortcuts for this specification.
Strong Acid Factor-of-10 pH Dilutions, Weak vs. Strong Acid Foils & Salt Preparation Methods
Every 10-fold increase in total volume V(final) / V(initial) = 10ᵏ increases strong acid pH by +k units (capped at pH 7). To shift pH by +k, you must add (10ᵏ - 1)*V(initial) of water.
Multi-Step Acid-Base Back-Titrations, Diprotic Ratios (H2SO4/Ca(OH)2), Thermometric Titration & Purity
Work in millimoles (mmol = c [mol dm⁻³] × V [cm³]) throughout! Proton-balance law: (# of H+ in acid) × c(acid) × V(acid) = (# of OH- in base) × c(base) × V(base). Always multiply aliquot moles by (V(flask) / V(pipette)) at the end.
Ready to Master Specification C9 Under Exam Conditions?
Practice timed questions under the authentic Pearson VUE interface with live split stopwatch pacing, dry-wipe scratchpad, and distractor forensics.