Question 1: Define a sulfate ion and write its chemical formula.

Answer: A sulfate ion is a polyatomic ion with the chemical formula SO₄²⁻.

Question 2: Explain the chemical reaction that occurs when a sulfate test is performed using barium chloride solution.

Answer: Barium chloride reacts with sulfate ions to form a insoluble barium sulfate precipitate, BaSO₄, which causes a white solid to form.

Question 3: Why is barium sulfate used in sulfate testing instead of other barium compounds?

Answer: Barium sulfate is insoluble in water, making it ideal for detecting sulfate ions without dissolving and interfering with the test.

Question 1: Calculate the mass of barium sulfate (BaSO₄) formed when 0.01 mol of sulfate ions react. (Molar mass of BaSO₄ = 233.39 g/mol)

Answer: Mass = 0.01 mol × 233.39 g/mol = 2.3339 g

Question 2: If 50 mL of a solution contains 0.002 mol of sulfate ions, what is the concentration of sulfate in mol/L?

Answer: Concentration = 0.002 mol / 0.050 L = 0.04 mol/L

Question 1: Describe the key safety precautions to observe when performing a sulfate test with barium chloride solution in the laboratory.

Answer: Wear safety goggles and gloves, avoid inhaling fumes, work in a well-ventilated area, and dispose of barium compounds properly as they are toxic.

Question 2: Identify the independent variable, dependent variable, and control in a sulfate test experiment where a student compares different concentrations of sulfate solutions.

Answer: Independent variable: concentration of sulfate solution; Dependent variable: amount of barium sulfate precipitate formed; Control variables: volume of solution, temperature, and amount of barium chloride used.

Question 1: A student tests three different solutions for sulfate ions. Solution A produces a large white precipitate, Solution B produces a small precipitate, and Solution C produces no precipitate. What can be inferred about the sulfate content in each solution?

Answer: Solution A has a high sulfate concentration, Solution B has a lower concentration, and Solution C likely has no sulfate ions.

Question 2: In an experiment, the precipitate weight for a sulfate solution was 1.5 grams. If the theoretical maximum precipitate weight for the given amount of sulfate is 2 grams, what percentage of the maximum precipitate was formed?

Answer: Percentage = (1.5 g / 2 g) × 100 = 75%

Question 1: Describe a step-by-step procedure to test whether a given solution contains sulfate ions, including safety precautions, reagents used, and how to interpret the results. Explain the scientific principles behind each step.

Answer: First, wear safety goggles and gloves. Add a few drops of the solution to a test tube. Add a few drops of dilute hydrochloric acid to remove carbonate impurities. Then, add a few drops of barium chloride solution. Observe if a white precipitate forms; if it does, sulfate ions are present. The formation of insoluble barium sulfate indicates a positive test. The principle relies on the formation of an insoluble sulfate compound with barium ions.

Question 1: Why is sulfate testing important in water quality analysis for drinking water supplies?

Answer: It helps detect the presence of sulfate ions, which can cause water taste issues, corrosion of pipes, and have health implications if levels are too high.

Question 2: Describe one industrial application where sulfate testing is crucial and explain why.

Answer: In the oil and gas industry, sulfate testing is used to monitor sulfate levels in produced water to prevent the formation of sulfate-reducing bacteria, which can cause corrosion and pipeline damage.