Igcse Model Questions Vol1 2017 Chemistry Question 3

Three unknown white solid samples are labelled A, B and C. The following experimental procedures are carried out on each sample: 1. Solubility test – a small amount of the solid is added to 20 mL of distilled water at room temperature. 2. Conductivity test – the resulting solution (if any) is placed between the electrodes of a conductivity tester. 3. Flame test – a clean nichrome wire is dipped into the solid and introduced into a non‑luminous Bunsen‑burner flame; any colour observed is recorded. The observations are recorded in the table below. | Sample | Solubility in water | Conductivity of solution | Flame colour | |--------|----------------------|--------------------------|--------------| | A | Dissolves completely | Conducts strongly | Green | | B | Does not dissolve | No conduction | No colour | | C | Dissolves sparingly | Weak conduction | No colour | Using the observations, answer the questions that follow.