Most important previous year question
1 marks questions
Q1 : Fe2O3 +2Al —> Al2O3 +2Fe
The above reaction is an example of :
(a) combination reaction
(b) double displacement reaction
(c) decomposition reaction
(d) displacement reaction.
Ans: The given equation is a displacement reaction in which Fe of Fe2O3 has been displaced by Al.
Thus Option (a) correct.
Q2: What happens when dilute hydrochloric acid is added to iron fillings? Tick the correct answer :
(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.
Ans :The following reaction takes place :
Fe+2HCl —> FeCl2 +H2
Thus, hydrogen and iron chloride are produced. Thus Option (a) correct.
Q3: Which of the following are exothermic processes ?
(i) Reaction of water with quicklime
(ii) Dilution of an acid
(iii) Evaporation of water
(iv) Sublimation of camphor (crystals)
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(a) (i) and (ii)
(b) (ii) and (iii)
(c) (iii) and (iv)
(d) (i) and (iv)
Ans :
(a) (i) and (ii)
Q4: Which among the following statement(s) is(are) true? Exposure of silver chloride to sunlight for a long duration turns grey due to :
(i) the formation of silver by decomposition of silver chloride
(ii) sublimation of silver chloride
(iii) decomposition of chlorine gas from silver chloride
(iv) oxidation of silver chloride
(a) (i) only
(b) (i) and (iii)
(d) (iv) only
(c) (ii) and (iii)
Ans :
(a) (i) only
Q5: In the double displacement reaction between aqueous potassium iodide and aqueous lead nitrate, a yellow precipitate of lead iodide is formed. While performing the activity if lead nitrate is not available, which of the following can be used in place of lead nitrate ?
(a) Lead sulphate (insoluble)
(b) Lead acetate
(c) Ammonium nitrate
(d) Potassium sulphate
Ans : (b) Lead acetate.
choose the correct option in next five question:
(a) Both Assertion and Reason are True and Reason is the correct explanation of the Assertion.
(b) Both Assertion and Reason are True but Reason is not the Correct explanation of the Assertion.
(c) Assertion is True but the Reason is False.
(d) Both Assertion and Reason are False.
Q6: Assertion : When water is added to calcium oxide, a large amount of heat is produced.
Reason : It is an endothermic reaction.
Ans : (c) Assertion is True but the Reason is False.
When water is added to calcium oxide, it forms calcium hydroxide with release of large amount of heat. Chemical reaction in which heat is released are called exothermic reactions. Hence, assertion is true but reason is false.
Q7: Assertion : Changing of colour of copper from reddish brown to black is an example of reduction.
Reason : Hydrogen is removed.
Ans : (d) Both Assertion and Reason are False. When we heat copper, it combines with oxygen to form black coloured copper (II). oxide. Loss of Hydrogen is known as oxidation and in this reaction no Hydrogen involved. So, both assertion and reason are false
Q8: Assertion : Silver chloride turns grey is sunlight.
Reason : Silver is one of the least reactive metals.
Ans :(b) Both Assertion and Reason are True but Reason is not the Correct explanation of the Assertion.
In the presence of sunlight, silver chloride decomposes to silver and chlorine. Silver is one of the least reactive metals as it lies at the bottom of the metal reactivity series. Both assertion and reason are true but reason does not explain assertion.
Q9: Assertion : Precipitation reactions produce insoluble salts.
Reason : Precipitation reaction is a double decomposition reaction.
Ans :(b) Both Assertion and Reason are True but Reason is not the Correct explanation of the Assertion. Precipitation reactions produce insoluble salts. Precipitation reaction is a double decomposition reaction but all double decomposition reactions are not precipitation reaction but only these reactions which form insoluble substances form precipitate. Hence both assertion and reason are true but reason does not explain assertion.
Q10: Assertion : Chips manufacturers usually flush bags of chips with oxygen gas.
Reason : It adds taste to chips.
Ans :(d) Both Assertion and Reason are False.
Chips manufactures usually flush bags of chips with inert gas such as nitrogen to prevent the chips from getting oxidised. Hence, both assertion and reason are false.
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