9.1 Qualitative Analysis: Tests for Ions

• Sodium ions (Na+) have a charge of +1.

  True
• To test for carbonate ions (CO3^2-), add dilute hydrochloric acid or sulfuric acid to produce carbon dioxide
• Adding barium chloride to a solution forms a white precipitate if sulfate ions are present.
• Qualitative analysis helps determine the purity of a substance.
• What is the charge of a calcium ion (Ca²⁺)?

  +2
• What gas is produced when carbonate ions react with hydrochloric acid?

  Carbon dioxide
• Adding barium chloride to a solution forms a white precipitate if sulfate ions are present.
• The reaction between chloride ions and silver nitrate forms a white precipitate of silver chloride.
• What brown/red gas is produced when nitrate ions react with sulfuric acid and copper turnings?

  Nitrogen dioxide
• Qualitative analysis is crucial for identifying the chemical composition of a substance.
• The brown/red gas produced in the nitrate ion test is called nitrogen
• Qualitative analysis helps determine the purity
• What is the charge of a sodium ion (Na+)?

  +1
• Which compound is used to test for sulfate ions?

  Barium chloride
• Which compound is used to test for chloride ions?

  Silver nitrate
• What reagent is used to test for chloride ions (Cl⁻)?

  Silver nitrate (AgNO3)
• What gas is produced when testing for nitrate ions (NO₃⁻)?

  Nitrogen dioxide (NO2)
• What observation indicates the presence of nitrate ions (NO₃⁻)?

  Brown/red gas
• What reagent is used to test for lead(II) ions (Pb²⁺)?

  Sodium iodide (NaI)
• A blue precipitate of copper(II) hydroxide (Cu(OH)₂) forms when testing for copper(II) ions (Cu²⁺)


  True
• What is the primary goal of qualitative analysis?

  Identifying chemical composition
• What is the charge of a sulfate ion (SO4^2-)?

  -2
• When carbonate ions react with hydrochloric acid, they produce carbon dioxide gas, which is observed as bubbles
• A white precipitate of barium sulfate (BaSO4) indicates the presence of sulfate ions.


  True
• The formation of a white precipitate of silver chloride confirms the presence of chloride ions.


  True
• To test for chloride ions, we add silver nitrate
• What is the balanced chemical equation for the reaction between nitrate ions, copper, and sulfuric acid?

  4NO_{3}^{ - } + 3Cu + 4H^{ + } \rightarrow 2NO + 2NO_{2} + 3Cu^{2 + } + 2H_{2}O</latex>
• The brown/red gas produced in the nitrate ion test is nitrogen dioxide.


  True
• To test for lead(II) ions, we add sodium iodide
• What is the balanced chemical equation for the reaction between copper(II) ions and sodium hydroxide?

  $Cu^{2 + } +$$2OH^ - \rightarrow Cu(OH)_{2}(s)$
• Safety precautions are crucial in qualitative analysis due to the use of hazardous chemicals.


  True
• Common cations include sodium (Na+), potassium (K+), calcium (Ca2+), and copper
• Common anions include chloride (Cl-), sulfate (SO4^2-), carbonate (CO3^2-), and nitrate
• What is the charge of a sulfate ion (SO4^2-)?

  -2
• Bubbles of CO2 gas are produced when dilute acid is added to carbonate ions (CO3^2-).


  True
• To test for sulfate ions (SO4^2-), add barium chloride (BaCl2), which forms a white precipitate of barium sulfate
• What precipitate forms when barium chloride reacts with sulfate ions?

  Barium sulfate
• What is the purpose of qualitative analysis?

  Identifying chemical components
• Steps in testing for carbonate ions (CO₃²⁻)

  1️⃣ Add dilute hydrochloric acid

  2️⃣ Bubbles of carbon dioxide are produced

  3️⃣ Test gas with limewater

  4️⃣ Limewater turns cloudy
• What precipitate forms when barium chloride reacts with sulfate ions?

  Barium sulfate