Question 1: Sulfates are a group of chemical compounds containing the sulfate ion, SO₄²⁻. They are commonly found in minerals, industrial products, and biological systems. Testing for sulphates involves specific chemical reactions that produce observable results.

Answer: Sulfates are compounds containing the SO₄²⁻ ion; tests involve adding acids and barium chloride to produce a white precipitate.

Question 1: Describe the chemical test used to identify sulphate ions in a solution.

Answer: Add dilute hydrochloric acid to remove carbonate ions, then add barium chloride solution; a white precipitate indicates sulphate ions.

Question 2: Explain why dilute hydrochloric acid is added before the barium chloride in the sulphate test.

Answer: To remove carbonate ions which could also form a precipitate and give a false positive.

Question 1: Design a simple experiment to test whether a given solution contains sulphate ions. Include the reagents needed, safety precautions, and how you would interpret the results.

Answer: Add dilute hydrochloric acid to the solution to eliminate carbonate ions, then add barium chloride solution. A white precipitate indicates the presence of sulphate ions. Wear safety goggles and gloves to handle acids and barium compounds; dispose of waste safely.

Question 1: A student tests three samples: Sample A produces a white precipitate with barium chloride, Sample B produces no precipitate, and Sample C produces a grey precipitate. Identify which samples contain sulphate ions and justify your answer.

Answer: Sample A contains sulphate ions based on the white precipitate. Sample B does not contain sulphates as no precipitate formed. Sample C's grey precipitate suggests contamination or presence of other ions.

Question 1: Calculate the molar mass of BaSO₄ in grams per mole (g/mol).

Answer: Molar mass of Ba = 137 g/mol, S = 32 g/mol, O₄ = 64 g/mol; total = 137 + 32 + 64 = 233 g/mol.

Question 1: Why is it important for water treatment plants to test for sulphate ions? Discuss potential consequences of high sulphate levels in drinking water.

Answer: High sulphate levels can cause laxative effects and taste issues. Sulphates can also lead to the formation of scale in pipes and equipment, reducing efficiency and causing damage.

Question 1: Describe in detail the chemical reaction involved when a sulphate ion reacts with barium chloride. Include the ionic equation and explain the significance of the precipitate formed.

Answer: When sulphate ions (SO₄²⁻) react with barium chloride (BaCl₂), they form barium sulfate (BaSO₄), a white insoluble precipitate. The ionic equation is: Ba²⁺ + SO₄²⁻ → BaSO₄(s). This reaction confirms the presence of sulphate ions in a solution through the formation of the characteristic precipitate.