Salt preparations
2 marks · HardState the general solubility rules for carbonates and hydroxides of common metals in water.
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Most carbonates and hydroxides are insoluble, except those of sodium, potassium, and ammonium.
Also accept: All sodium, potassium, and ammonium carbonates and hydroxides are soluble; other carbonates and hydroxides are insoluble or almost insoluble.; The only soluble carbonates and hydroxides are those of sodium, potassium, and ammonium.
Common mistakes: Saying all are soluble or only all carbonates are insoluble
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Marking points
B1 · 1 mark · States most carbonates and hydroxides are insoluble in water.
B2 · 1 mark · Identifies the exceptions: sodium, potassium, and ammonium carbonates and hydroxides are soluble.
Worked solution
Most carbonates and hydroxides are insoluble in water, except those of sodium, potassium, and ammonium, which are soluble.