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41. Which among the following is (are) double displacement reactions ? [NCERT Exemplar Problems]
(i) Pb + CuCl2 → PbCl2 + Cu
(ii) Na2SO4 + BaCl2 → BaSO4 + 2NaCl
(iii) C + O2 → CO2
(iv) CH4 + 2O2 → CO2 + 2H2O
(a) (i) and (iv)
(b) (ii) only
(c) (i) and (ii)
(d) (iii) and (iv)
Answer
Answer: b
42. Barium chloride on reacting with ammonium sulphate forms barium sulphate and ammonium chloride. Which of the following correctly represents the type of the reaction involved ? [NCERT Exemplar Problems]
(i) Displacement reaction
(ii) Precipitation reaction
(iii) Combination reaction
(iv) Double displacement reaction
(a) (i) only
(b) (ii) only
(c) (iv) only
(d) (ii) and (iv)
Answer
Answer: d
43. Electrolysis of water is a decomposition reaction. The molar ratio of hydrogen and oxygen gases liberated during electrolysis of water is [NCERT Exemplar Problems]
(a) 1 : 1
(b) 2 : 1
(c) 4 : 1
(d) 1 : 2
Answer
Answer: b
44. Which of the following is (are) an endothermic process(es) ? [NCERT Exemplar Problems]
(z) Dilution of sulphuric acid
(ii) Sublimation of dry ice
(iii) Condensation of water vapours
(iv) Evaporation of water
(a) (i) and (iii)
(b) (ii) only
(c) (iii) only
(d) (ii) and (iv)
Answer
Answer: d
45. Which of the following gases can be used for storage of fresh sample of an oil for a long time? [NCERT Exemplar Problems]
(a) Carbon dioxide or oxygen
(b) Nitrogen or oxygen
(c) Carbon dioxide or helium
(d) Helium or nitrogen
Answer
Answer: d
46. The following reaction is used for the preparation of oxygen gas in the laboratory
Which of the following statement(s) is (are) correct about the reaction ? [NCERT Exemplar Problems]
(a) It is a decomposition reaction and endothermic in nature
(b) It is a combination reaction
(c) It is a decomposition reaction and accompanied by release of heat
(d) It is a photochemical decomposition reaction and exothermic in nature
Answer
Answer: a
47. Which one of the following processes involve chemical reactions ? [NCERT Exemplar Problems]
(a) Storing of oxygen gas under pressure in a gas cylinder
(b) Liquefaction of air
(c) Keeping petrol in a china dish in the open
(d) Heating copper wire in presence of air at high temperature
Answer
Answer: d
48. In which of the following chemical equations, the abbreviations represent the correct states of the reactants and products involved at reaction temperature ? [NCERT Exemplar Problems]
(a) H2(l) + O2(l) → 2H2O(g)
(b) H2(g) + O2(l) → 2H2O(l)
(c) H2(g) + O2(g) → 2H2O(l)
(d) H2(g) + O2(g) → m2O(g)
Answer
Answer: c
49. The brown gas evolved on heating of copper nitrate is
(a) O2
(b) NO2
(c) N2
(d) NO
Answer/Explanation
Answer: b
Explanation:
50. Zinc reacts with silver nitrate to form which compounds?
(a) Zn(NO3)2 + Ag
(b) ZnNO3 + Ag
(c) AgNO3 + Zn(NO3)2
(d) Ag + Zn(NO3)3
Answer/Explanation
Answer: a
Explanation:
(a) Zn + 2AgNO3 → Zn(NO3)2 + 2Ag
51. MnO2 + 4HCl → MnCl2 + H2O + Cl2 The oxidising agent is
(a) MnO2
(b) HCl
(c) MnCl2
(d) Ag + Zn(NO3)3
Answer/Explanation
Answer: a
Explanation:
(a) MnO2 is oxidising agent because it is removing hydrogen from HCl to form Cl2.
52.
The colour of iodine is
(a) green
(b) purple
(c) brown
(d) pink
Answer/Explanation
Answer: b
Explanation:
(b) Iodine is purple in colour.
Direction (Q53 to Q57): In the following Questions, the Assertion and Reason have been put forward. Read the statements carefully and choose the correct alternative from the following:
(a) Both the Assertion and the Reason are correct and the Reason is the correct explanation of the Assertion.
(b) The Assertion and the Reason are correct but the Reason is not the correct explanation of the Assertion.
(c) Assertion is true but the Reason is false.
(d) The statement of the Assertion is false but the Reason is true.
53. Assertion: AgBr is used on photographic and x-ray film.
Reason: AgBr is photosensitive and changes to Ag and bromine in presence of sunlight and undergoes decomposition reaction.
Answer/Explanation
Answer: a
Explanation:
(a) Both the Assertion and the Reason are correct and the Reason is the correct explanation of the Assertion.
54. Assertion: Magnesium ribbon keeps on burning in atmosphere of nitrogen. Reason: Magnesium reacts with nitrogen to form magnesium nitrides and this reaction is combination reaction.
Answer/Explanation
Answer: a
Explanation:
(a) Both the Assertion and the Reason are correct and the Reason is the correct explanation of the Assertion.
55. Assertion: Zinc reacts with sulphuric acid to form zinc sulphate and hydrogen gas and it is displacement reaction.
Reason: Zinc reacts with oxygen to form zinc oxide.
Answer/Explanation
Answer: b
Explanation:
(b) The Assertion and the Reason are correct but the Reason is not the correct explanation of the Assertion.
56. Assertion: MnO2 + 4HCl → MnCl2 + Cl2 + 2H2O is redox reaction.
Reason: MnO2 oxides HCl to Cl2 and gets reduced to MnCl2.
Answer/Explanation
Answer: a
Explanation:
(a) Both the Assertion and the Reason are correct and the Reason is the correct explanation of the Assertion.
57. Assertion: A lead nitrate on thermal decomposition gives lead oxide, brown coloured nitrogen dioxide and oxygen gas. Reason: Lead nitrate reacts with potassium iodide to form yellow ppt of lead iodide and the reaction is double displacement as well as precipitation reaction.
Answer/Explanation
Answer: b
Explanation:
(b) The Assertion and the Reason are correct but the Reason is not the correct explanation of the Assertion.
58. The colour of FeSO4 crystal before ___________ heating is and after heating is ___________ .
Answer/Explanation
Answer:
Explanation: green, reddish brown
59. SO2 + 2H2S → 2H2O + 3S; SO2 is ___________ acting as agent.
Answer/Explanation
Answer:
Explanation: oxidising
60. The reaction Cu + xHNO3 (cone.) → Cu(NO3)2 + yNO2 + zH2O The values of x, y and z are ___________ , ___________ and ___________ .
Answer/Explanation
Answer:
Explanation: 4, 2 and 2
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