Ijmb Model Questions Vol1 2025 Chemistry Question 3

A laboratory investigation was carried out to determine the type of chemical bonding present in three different substances. The following observations were recorded: 1. **Sample A** – a solid copper wire was connected to a digital multimeter. The resistance measured was 0.02 Ω. 2. **Sample B** – a dry crystalline solid of refined sucrose (table sugar) was placed between the same electrodes. No current was recorded (infinite resistance). 3. **Sample C** – 25 mL of an aqueous solution prepared by dissolving an unknown white solid in 100 mL of distilled water. The solution was clear and colourless. Conductivity of the solution was measured as 1.20 S m⁻¹. When a few drops of 0.1 M AgNO₃ solution were added, a white precipitate formed instantly. Using the data above, answer the questions that follow.