A mixture C contains lead(II) carbonate and starch. Describe the qualitative analysis tests to identify the components.

Here is a simplified explanation of the qualitative analysis:

• Test 1: Mixing C with distilled water

  • Observation: The mixture remains a white solid and does not dissolve.
  • Conclusion: C contains substances that are insoluble in water.

• Test 2: Adding dilute hydrochloric acid (HCl) or nitric acid ($\text{HNO}_3$) to C

  • Observation: Fizzing occurs, and a colorless, odorless gas is produced. This gas turns lime water milky.
  • Conclusion: Carbonate ions ($\text{CO}_3^{2-}$) are present, as carbon dioxide ($\text{CO}_2$) gas is evolved.

• Test 3: Heating and cooling the liquid part (filtrate) from the acid test

  • Observation: A white solid dissolves upon heating and reappears when cooled.
  • Conclusion: Lead(II) ions ($\text{Pb}^{2+}$) are present.

• Test 4: Adding ammonia solution ($\text{NH}_3(\text{aq})$) to the filtrate

  • Observation: A white solid forms, which does not dissolve even with excess ammonia.
  • Conclusion: This confirms the presence of lead(II) ions ($\text{Pb}^{2+}$).

• Test 5: Adding sodium hydroxide solution ($\text{NaOH}(\text{aq})$) to the filtrate

  • Observation: A white solid forms initially, then dissolves when excess sodium hydroxide is added.
  • Conclusion: This also confirms the presence of lead(II) ions ($\text{Pb}^{2+}$).

• Test 6: Adding iodine solution to a portion of the original mixture

  • Observation: The mixture turns blue-black or dark blue.
  • Conclusion: Starch is present.