Reactions in Aqueous Solutions

Info

Mixing 2 aqueous solutions may result in:

  1. No reaction (ions remain in solution)
    • All chemicals remain the same state
  2. A reaction occurs
    • becomes a precipitate

In an aqueous solution a double displacement reaction can result in the formation of:

  1. A gas ()
    • E.g solid lithium hydride and water produces aqueous lithium hydroxide and hydrogen gas:
  2. Water
  3. A precipitate (insoluble solid)
    • E.g aqueous potassium carbonate and aqueous copper (II) sulfate produces potassium sulfate and copper (II) carbonate

Solubility Rules

Rules

In general, the following solubility rules can be followed:

  1. All nitrates are soluble ()
  2. Alkali metal ions and ions are soluble
  3. Halides (group 7, ) are soluble except when reacted with (heavy metals)
  4. Most sulfates are soluble, except when reacted with (heavy metals)
  5. Most hydroxides are slightly soluble (insoluble) except and
  6. Sulfides, carbonates, chromates, and phosphates are insoluble

Predicting Precipitates

Definition

Experimentally, a precipitate is seen as sudden cloudiness or an obvious solid formed when the 2 solutions are mixed

A solubility table or solubility rules can be used to predict which of the possible products formed is the precipitate.

Example

Aqueous sodium chloride and aqueous silver nitrate react. Predict the precipitate.

solution
molecular formula:

Silver chloride forms a precipitate.

Ionic equation:

Net-ionic equation:

Spectator ions: