Page 69 - Chemistry ICSE Class IX
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Chemical Changes and Reactions 57
(ii) The reaction, H + Cl o 2HCl is
2
2
(a) an oxidation reaction (b) a reduction reaction
(c) a combination reaction (d) an isomerisation reaction
(iii) When a chemical species loses one or more electrons, it is said to have been
(a) oxidised (b) reduced
(c) decomposed (d) displaced
(iv) When sodium metal is dropped into water, it gets
(a) oxidised (b) reduced
(c) remain unchanged (d) hydrolysed
(v) In the reaction, H S + Cl o 2HCl + S, the electrons are transferred from
2
2
2–
(a) S to S (b) Cl to HCl
2
2–
(c) S to Cl (d) H S to S
2
2
(vi) Which of the statements about the reaction given below are incorrect?
2PbO(s) + C(s) o 2Pb(s) + CO (g)
2
(1) lead is getting reduced (2) carbon dioxide is getting oxidised
(3) carbon is getting oxidised (4) lead oxide is getting reduced
(a) (1) and (2) (b) (1) and (3)
(c) (1), (2) and (3) (d) all
[Hint: Here, PbO is getting reduced to Pb, and C is getting oxidised to CO ]
2
(vii) What happens when dilute hydrochloric acid is added to iron lings?
(a) Hydrogen gas and iron chloride are produced
(b) Chlorine gas and iron hydroxide are produced
(c) No reaction takes place
(d) Iron salt and water are produced
[Hint: Fe(s) + 2HCl(aq) o FeCl (aq) + H (g)
2
2
iron hydrochloric acid iron(II) chloride hydrogen
(viii) The reaction, Fe O (s) + 2Al(s) o Al O (s) + 2Fe(l), is an example of
3
3
2
2
(a) combination reaction (b) double displacement reaction
(c) decomposition reaction (d) displacement reaction
[Hint: Here, aluminium displaces iron from Fe O ]
3
2
(ix) Which of the following has the lowest ignition temperature?
(a) paper (b) wood
(c) petrol (d) water
(x) The product of partial combustion of a fossil fuel, which is highly poisonous is
(a) carbon dioxide (b) carbon monoxide
(c) oxides of nitrogen (d) oxides of sulphur
Answers
(i) (b) (ii) (c) (iii) (a) (iv) (a) (v) (c) (vi) (a) (vii) (a) (viii) (d)
(ix) (c) (x) (b)
