Making predictions using the reactivity series
3 marks · EasyA new metal, Q, lies between magnesium and zinc in the reactivity series.
Predict whether metal Q will react with cold water. State your reasoning.
Predict whether metal Q will react with dilute hydrochloric acid at room temperature. State your reasoning.
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(a) No, Q will not react with cold water because only metals above magnesium react rapidly with cold water. · must show Correct prediction, Reason linked to position in series
(b) Yes, Q will react with dilute hydrochloric acid, forming a salt and hydrogen gas, because metals above hydrogen, including those between magnesium and zinc, react with acids at room temperature. · must show Correct prediction, Reason linked to position in series, Mention of salt and hydrogen gas formed
Common mistakes: Assuming all metals between magnesium and zinc react with water; Not linking the prediction to the position in reactivity series
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Marking points
B1 (a) · 1 mark · Correct prediction and clear linked reasoning for lack of reaction with cold water
B2 (b) · 1 mark · Correct prediction of reaction with dilute acid
B3 (b) · 1 mark · Correct explanation: position in reactivity series or reference to forming salt and hydrogen
Worked solution
a) Metal Q will not react with cold water. Only metals above magnesium in the reactivity series (such as sodium, potassium, calcium) react rapidly with cold water. Q is below magnesium, so no reaction is expected.
b) Metal Q will react with dilute hydrochloric acid because metals between magnesium and zinc are above hydrogen in the reactivity series. They react with acids to produce a salt and hydrogen gas. So, Q will fizz (give off hydrogen gas) and form a chloride salt.