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2020 O Level Chem P1 Q26 — Metals / Reactivity Series and Extraction Solution

Metals / Reactivity Series and Extraction 2020 O Level Pure Chemistry · Paper 1 · Q26

Question

X is a metal. It occurs naturally as an element and sometimes in ores containing its oxide. X can be used to make a chloride of formula XCl but no other chloride of X exists. A student made some statements about metal X. 1 It can be displaced from solutions containing its ions according to the equation below. 3X⁺(aq) + Fe(s) → Fe³⁺(aq) + 3X(s) 2 It can be extracted from its ore by electrolysis. 3 It can be extracted from its ore by reduction with carbon. 4 It is likely to be found as an ore containing the compound X₂O₃. Which statements are correct?

A1, 2 and 3
B1 and 3 only
C2 and 3 only
D3 and 4

Correct answer: B

Video Solution

Explanation

Answer: B (1 and 3 only). The clues identify X as an unreactive metal. It forms only the chloride XCl, so X is +1, and the equation \(3\text{X}^+ + \text{Fe} \to \text{Fe}^{3+} + 3\text{X}\) shows iron displacing X, so X is less reactive than iron. Occurring naturally as the free element also points to a very unreactive metal such as silver.

Statement 1 is correct: since iron is more reactive than X, iron can displace X from a solution of its ions, exactly as the equation shows. Statement 3 is correct: a metal below carbon in the reactivity series can be extracted by reduction with carbon. Statement 2 is wrong: electrolysis is reserved for very reactive metals above carbon, which X is not. Statement 4 is wrong: since X is +1, its oxide would be X₂O, not X₂O₃.

So statements 1 and 3 are correct, giving answer B.

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