5.5.3 Precipitation reactions

• What is a precipitation reaction?

  Formation of an insoluble solid
• In a precipitation reaction, the insoluble solid is observed as cloudiness or particles settling at the bottom.


  True
• Iron(III) hydroxide, Fe(OH)₃, is a brown precipitate formed in precipitation reactions.brown
• What precipitate forms when silver(I) ions react with chloride ions?

  AgCl
• Salts of alkali metals are generally soluble in water with no exceptions
• All sulfates are soluble except those of silver, barium, lead, and calcium.


  True
• Sodium chloride (NaCl) is soluble in water because it's a salt of alkali metals.


  True
• The balanced chemical equation for the reaction between iron(II) ions and hydroxide ions is Fe²⁺ + 2OH⁻ → Fe(OH)₂.
• Insoluble salts are referred to as precipitates in precipitation reactions.


  True
• The general form of a balanced precipitation reaction equation is: Cation^x+ + Anion^y- → Precipitate
• What are the two types of ions that make up soluble salts in precipitation reactions?

  Cation and anion
• Solubility rules are used to determine which precipitate will form in a reaction.


  True
• Steps to predict the products of a precipitation reaction:

  1️⃣ Identify soluble salts

  2️⃣ Determine the insoluble salt

  3️⃣ Write the balanced chemical equation
• Salts of alkali metals are always soluble
• Match the anion with the ion that makes its salts insoluble:

  Chlorides ↔️ Silver

  Sulfates ↔️ Barium

  Carbonates ↔️ Alkali metals

  Hydroxides ↔️ Ammonium
• What is the general form for writing a balanced chemical equation in a precipitation reaction?

  Cation^x+ + Anion^y- → Precipitate
• What is the precipitate formed when copper(II) sulfate reacts with sodium hydroxide?

  Copper(II) hydroxide
• Insoluble salts form precipitates in water.

  True
• What are the exceptions to the solubility of chlorides, bromides, and iodides?

  Silver and lead
• Insoluble salts do not dissolve significantly in water and form a precipitate
• All salts of alkali metals are soluble.

  True
• Carbonates are generally insoluble except when combined with alkali metals or ammonium
• Why is NaCl soluble in water?

  It's a salt of an alkali metal
• Why is BaSO₄ insoluble in water?

  Barium is an exception
• All salts of alkali metals are soluble.


  True
• Steps to write a balanced chemical equation for a precipitation reaction

  1️⃣ Identify the soluble salts being mixed

  2️⃣ Determine the insoluble salt (precipitate)

  3️⃣ Write the balanced equation
• What is the balanced equation for the reaction between silver ion and chloride ion?

  $Ag^ +$$+$$Cl^ - → AgCl$
• Chlorides are generally soluble except when combined with silver
• Copper(II) hydroxide is a blue precipitate.
• What is the balanced chemical equation for the reaction between copper(II) ions and hydroxide ions?

  $Cu^{2 + } +$$2OH^ - \rightarrow Cu(OH)_{2}$
• In precipitation reactions, observing the colour and physical state of the precipitate helps identify the products.


  True
• Iron(III) hydroxide is a brown precipitate with a fluffy suspension
• Match the precipitate with its colour and physical state:

  $Cu(OH)_{2}$ ↔️ Blue, cloudy liquid

  $Fe(OH)_{3}$ ↔️ Brown, fluffy suspension

  $AgCl$ ↔️ White, creamy solid
• How does temperature affect the solubility product constant (Ksp)?

  Increases with higher temperature
• Arrange the following applications of precipitation reactions in everyday life in order of their primary purpose:

  1️⃣ Water Treatment

  2️⃣ Wastewater Treatment

  3️⃣ Analytical Chemistry

  4️⃣ Pharmaceuticals
• Which precipitant is used to remove phosphate ions in wastewater treatment?

  Iron(III) chloride
• What is an example of precipitation in pharmaceuticals?

  Crystallizing proteins
• A precipitation reaction occurs when two solutions containing soluble salts are mixed, resulting in the formation of an insoluble solid called a precipitate
• What is the color of copper(II) hydroxide, Cu(OH)₂?

  Blue
• Match the transition metal ion with its precipitate color when reacted with hydroxide ions:

  Fe²⁺ ↔️ Green

  Fe³⁺ ↔️ Brown

  Cu²⁺ ↔️ Blue