Home › TYS Solutions › O Level Chem › 2018 › P1 Q28

2018 O Level Chem P1 Q28 — Metals / Alloys Solution

Metals / Alloys 2018 O Level Pure Chemistry · Paper 1 · Q28

Question

Which statement about alloys is correct?

AThey are good conductors of electricity as they have mobile ions.
BThey are formed by a chemical reaction between two metals.
CThey can all be represented by a molecular formula.
DTheir structures contain a 'sea of electrons'.

Correct answer: D

Video Solution

Explanation

Answer: D (their structures contain a sea of electrons). An alloy is a mixture of a metal with one or more other elements. It keeps the metallic structure of a lattice of cations surrounded by a sea of delocalised electrons; the different-sized atoms disrupt the orderly layers, making the alloy harder than the pure metal.

A is wrong: metals and alloys conduct through mobile electrons, not mobile ions. B is wrong: alloying is a physical process (melt, mix, cool), not a chemical reaction. C is wrong: alloys are mixtures, so they have no fixed molecular formula. Answer D.

Get the Sec 3 / Sec 4 recording package

Every O Level Pure Chemistry TYS MCQ solution video, plus full Sec 3 / Sec 4 topic recordings.