Question 1: Define what a halide ion is.

Answer: A halide ion is a negatively charged ion (anion) derived from a halogen element, such as chloride (Cl⁻), bromide (Br⁻), or iodide (I⁻).

Question 2: Explain the principle behind testing for halide ions using silver nitrate solution.

Answer: Silver nitrate reacts with halide ions to form insoluble silver halide precipitates, which have characteristic colours, allowing identification of the halide present.

Question 3: List the colours of the precipitates formed when testing chloride, bromide, and iodide ions with silver nitrate.

Answer: Chloride: White, Bromide: Cream, Iodide: Pale yellow.

Question 1: Calculate the mass of silver nitrate (AgNO₃, molar mass = 169.87 g/mol) needed to completely react with 0.5 g of sodium bromide (NaBr).

Answer: Mass of AgNO₃ = (0.5 g NaBr) × (1 mol NaBr / 102.89 g) × (1 mol AgNO₃ / 1 mol NaBr) × 169.87 g/mol ≈ 0.826 g

Question 2: If a solution contains 0.02 mol of chloride ions per litre, how many grams of sodium chloride (NaCl, molar mass = 58.44 g/mol) are in 250 mL of this solution?

Answer: Mass = 0.02 mol/L × 0.25 L × 58.44 g/mol ≈ 0.292 g

Question 1: Describe the safety precautions that should be taken when handling silver nitrate solution during halide tests.

Answer: Silver nitrate is corrosive and can stain skin and clothing. Students should wear gloves and eye protection, handle the solution carefully, and dispose of waste properly.

Question 2: Identify the independent and dependent variables in an experiment testing for halide ions using silver nitrate solution.

Answer: Independent variable: the type of halide ion present; Dependent variable: the colour or appearance of the precipitate formed.

Question 1: A solution tested with silver nitrate produces a cream precipitate. Which halide ion is most likely present? Justify your answer.

Answer: Bromide ion, because it forms a cream precipitate with silver nitrate.

Question 1: Explain how the detection of halide ions is important in the pharmaceutical industry.

Answer: Detecting halide ions ensures the purity of pharmaceuticals, prevents contamination, and helps identify the presence of unwanted substances that could affect drug safety and efficacy.