Compound A is a chloride of a Period 3 element.
A student carries out the 2 steps below to find the formula of compound A.
Step 1 The student adds 4.00×10−4 mol4.00 \times 10^{-4} \text{ mol}4.00×10−4 mol of compound A to water. A colourless solution is formed.
Step 2 The colourless solution reacts with exactly 80.0 cm380.0 \text{ cm}^380.0 cm3 of 2.00×10−2 mol dm−3 AgNO3(aq)2.00 \times 10^{-2} \text{ mol dm}^{-3} \text{ AgNO}_3\text{(aq)}2.00×10−2 mol dm−3 AgNO3(aq) to form a white precipitate.
Write an ionic equation, with state symbols, for the reaction in Step 2.
Determine the formula of compound A.
