Examkin

Question

Difficulty: EasyTypes and Preparation Methods of Salts

Which of the following methods is most suitable for preparing lead(II) sulfate (PbSO4PbSO_4), an insoluble salt, in the laboratory?

  1. A
    Neutralization of dilute tetraoxosulfate(VI) acid with aqueous lead(II) nitrate solution by titration
  2. B
    Direct combination of lead metal and concentrated tetraoxosulfate(VI) acid
  3. Double decomposition between aqueous lead(II) nitrate and aqueous sodium sulfateAnswer
  4. D
    Action of dilute tetraoxosulfate(VI) acid on insoluble lead(II) carbonate followed by evaporation to dryness

Answer

Double decomposition between aqueous lead(II) nitrate and aqueous sodium sulfate.
Insoluble salts such as lead(II) sulfate (PbSO4PbSO_4) are prepared in the laboratory by double decomposition (precipitation), where two aqueous solutions containing soluble salts are mixed to precipitate the desired insoluble salt.

Step-by-Step Solution

1
Identify the solubility of the target salt
Lead(II) sulfate (PbSO4PbSO_4) is insoluble in water.
The choice of preparation method depends primarily on whether the salt is soluble or insoluble.
2
Select the appropriate synthesis method for insoluble salts
Insoluble salts are best prepared by double decomposition (precipitation) using two soluble salts as starting materials.
Mixing solutions containing Pb2+Pb^{2+} ions (e.g., Pb(NO3)2(aq)Pb(NO_3)_2(aq)) and SO42−SO_4^{2-} ions (e.g., Na2SO4(aq)Na_2SO_4(aq)) results in the immediate precipitation of insoluble PbSO4(s)PbSO_4(s).
3
Formulate the balanced chemical equation
Pb(NO3)2(aq)+Na2SO4(aq)→PbSO4(s)+2NaNO3(aq)Pb(NO_3)_2(aq) + Na_2SO_4(aq) \rightarrow PbSO_4(s) + 2NaNO_3(aq)
The insoluble lead(II) sulfate precipitates out and can easily be collected by filtration, washed with distilled water, and dried.

Key Concept

Preparation of insoluble salts by precipitation (double decomposition)
Rate this question

Topics

Types and Preparation Methods of Salts

More questions from this topic