O-LevelChemistryMetals & Reactivity5070/22 · May/June 2015 · Q710 Marks

Titanium can be manufactured by heating titanium(IV) chloride, TiCl4, with magnesium.

(a)Construct the equation for this reaction.[1]
(b)Explain why this reaction involves both oxidation and reduction.[2]
(c)What mass of titanium can be made from 125 g of titanium(IV) chloride?[3]
(d)Which metal is the less reactive, magnesium or titanium? Explain your answer.[1]
(e)Titanium(IV) chloride is a liquid with a low boiling point of 126°C. Suggest the structure and bonding of titanium(IV) chloride.[2]
(f)Explain how titanium metal conducts electricity.[1]

Mark scheme

Marking points from the official mark scheme (May/June 2015). The mark or mark type is shown in brackets.

[1] (a) TiCl4 + 2Mg → 2MgCl2 + Ti (1)
[2] (b) Reduction because Ti ions gain electrons/oxidation number of Ti decreases (1)
Oxidation since Mg loses electrons/oxidation number of Mg increases (1)
[3] (c) Mr of TiCl4 = 190 (1)
Moles of TiCl4 is 0.658/% of Ti = 25.3 (1)
Mass of Ti = 31.6 (g) (1)
[1] (d) Titanium because magnesium can displace titanium (1)
[2] (e) (Simple) molecular/reference to molecules (1)
Covalent (1)
[1] (f) Electron(s) can move/has delocalised electron(s) (1)

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