Waec Model Questions Vol1 2021 Chemistry Question 3

A student performed a series of qualitative tests on an unknown white crystalline solid labelled X. The observations are recorded in the table below. | Test | Observation | |------------------------------------|-----------------------------------------------------------| | Solubility in water | Dissolves with effervescence, forming a clear solution. | | Solubility in ethanol | Does not dissolve. | | Solubility in dilute HCl (0.1 M) | No change. | | Conductivity of 1 dm³ solution | High conductivity. | | Flame test | No colour observed. | | Reaction with AgNO₃ (2 mL) | White precipitate forms immediately. | A separate experiment was carried out by reacting 0.50 g of X with excess AgNO₃ solution. After filtration, 1.23 g of white precipitate (AgCl) was obtained. Answer the following questions: