2:34 know the general rules for predicting the solubility of ionic compounds in water: common sodium, potassium and ammonium compounds are soluble, all nitrates are soluble, common chlorides are soluble, except those of silver and lead(II), common sulfates are soluble, except for those of barium, calcium and lead(II), common carbonates are insoluble, except for those of sodium, potassium and ammonium, common hydroxides are insoluble except for those of sodium, potassium and calcium (calcium hydroxide is slightly soluble)

Salt	Solubility	Exceptions
sodium (Na⁺), potassium (K⁺) and ammonium (NH₄⁺)	soluble	none
nitrates (NO₃^-)	soluble	none
chlorides (Cl^-)	soluble	silver chloride (AgCl) and lead (II) chloride (PbCl₂)
sulfates (SO₄^2-)	soluble	barium sulfate (BaSO₄), calcium sulfate (CaSO₄) and lead (II) sulfate (PbSO₄)
carbonates (CO₃^2-)	insoluble	sodium carbonate (Na₂CO₃), potassium carbonate (K₂CO₃) and ammonium carbonate ((NH₄)₂CO₃)
hydroxides (OH^-)	insoluble	sodium hydroxide (NaOH), potassium hydroxide (KOH) and calcium hydroxide (Ca(OH)₂) (calcium hydroxide is slightly soluble)

Past paper questions on spec point:

Spec	Q'stion	Ans	MS
2:34	Jan '12 (2), Q 3 a i	Answer	MkS
2:34	Jan '12 (2), Q 3 b	Answer	MkS
2:34	Jan '13 (2), Q 5 b	Answer	MkS
2:34	Jan '14 (1), Q 5 b	Answer	MkS
2:34	Jan '15 (1), Q 5 c i	Answer	MkS
2:34	May '12 (1), Q 3 a	Answer	MkS
2:34	May '12 (1), Q 3 c i	Answer	MkS
2:34	May '13 (1R), Q 7 a	Answer	MkS
2:34	May '14 (2R), Q 5 a v	Answer	MkS
2:34	May '15 (1), Q 4 a	Answer	MkS
2:34	May '16 (2R), Q 7 a	Answer	MkS