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21. Name the products formed when iron filings are heated with dilute hydrochloric acid
(a) Fe (III) chloride and water
(b) Fe (II) chloride and water
(c) Fe (II) chloride and hydrogen gas
(d) Fe (III) chloride and hydrogen gas

Answer/ Explanation

Answer: d
Explaination: Reason: 2Fe + 6HCl → 2FeCl3 (Iron (III) chloride) + 3H2


22. Pb + CuCl2 → PbCl2 + Cu
The above reaction is an example of:
(a) combination
(b) double displacement
(c) decomposition
(d) displacement

Answer

Answer: d


23. Which of the following gases can be used for storage (a) Carbon dioxide or Oxygen
(b) Nitrogen or Oxygen
(c) Carbon dioxide or Helium
(d) Helium or Nitrogen

Answer

Answer: d


24. A dilute ferrous sulphate solution was gradu¬ally added to the beaker containing acidified permanganate solution. The light purple colour of the solution fades and finally disap¬pears. Which of the following is the correct explanation for the observation?
(a) KMnO4 is an oxidising agent, it oxidises FeSO4.
(b) FeSO4 acts as an oxidising agent and oxidises KMNO4.
(c) The colour disappears due to dilution; no reaction is involved.
(d) KMnO4 is an unstable compound and de-composes in presence of FeSO4. to a colourless compound.

Answer

Answer: a


25. In which of the following chemical equations, the abbreviations represent the correct states of the reactants and products involved at reaction temperature?
(a) 2H2 (l) + O2 (l) > 2H2O(g)
(b) 2H2 (g) + O2 (l) > 2H2O (l)
(c) 2H2 (g) + O2 (g) > 2H2O (l)
(d) 2H2 (g) +O2 (g) > 2H2O (g)

Answer

Answer: d


26. When green coloured ferrous sulphate crystals are heated, the colour of the crystal changes because
(a) it is decomposed to ferric oxide
(b) it loses water of crystallisation
(c) it forms SO2
(d) it forms SO3

Answer

Answer: b


27. 2HNO3 + Ca(OH)2 → Ca(NO3)2 + 2H2O; is an example of
(i) displacement reaction
(ii) double displacement reaction
(iii) neutralisation reaction
(iv) combination reaction.
(a) (i) and (ii)
(b) (ii) and (iii)
(c) (iii) and (iv)
(d) (i) and (iv)

Answer

Answer: b


28. Burning Magnesium ribbon is brought in the gas jar of carbon dioxide. Which of the following is correct ?
(i) It keeps on burning
(ii) It gets extinguished
(iii) Although CO2 is non-supporter of combustion but burning magnesium breaks CO2 into carbon and oxygen, oxygen helps in burning.
(iv) Carbon dioxide is supporter of combustion.
(a) (i) and (iv)
(b) (i) and (iii)
(c) (i) and (ii)
(d) (iii) and (iv)

Answer

Answer: b


29. What is observed when a solution of potassium iodide is added to silver nitrate solution ?
(a) No reaction takes place
(b) White precipitate of silver iodide is formed
(c) yellow precipitate of Agl is formed
(d) Agl is soluble in water.

Answer

Answer: c


30. Identify ‘x’, ‘y’ and ‘z’ in the following balanced reaction

(a) 2, 4, 2
(b) 2, 2, 4
(c) 2, 4, 4
(d) 4, 2, 2

Answer

Answer: b


31. Which of the following is precipitation as well as double displacement reaction?

Answer

Answer: d


32. Which of the following reactions will not take place ?
(a) Zn + CuSO4 → ZnSO3 + Cu
(b) 2KBr + Cl2 → KCl + Br2
(c) Zn + MgSO4 → ZnSO4 + Mg
(d) Mg + FeSO4 → MgSO4 + Fe

Answer

Answer: c


33. Which of the following involves combination of two elements ?
(a) N2(g) + 3H2(g) → 2NH3(g)
(b) CaO(s) + CO2(g) → CaCO3(g)
(c) 2SO2(g) + O2(g) → 2SO3f(g)
(d) NH3(g) + HCl(g) → NH4Cl(s)

Answer

Answer: a


34. In the reaction Hg2Cl2 + Cl2 → 2HgCl2 The reducing agent is
(a) Hg2Cl2
(b) Cl2
(c) HgCl2
(d) Both Cl2 and HgCl2

Answer

Answer: a


35. Oxidation involves
(i) gain of electron
(ii) loss of electron
(iii) addition of oxygen or electronegative element
(iv) removal ofhydrogenorelectropositive element
(a) (i), (ii), (iii)
(b) (ii), (iii), (iv)
(c) (i), (iii), (iv)
(d) (i), (ii), (iv)

Answer

Answer: b


36. The formula of Ammonium phosphate is
(a) NH4PO4
(b) (NH4)2PO4
(c) (NH4)3PO4
(d) (NH4)3(PO4)2

Answer

Answer: c


37. Which of the following is a thermal decomposition reaction ?
(a) 2H2O → 2H2 + O2
(b) 2AgCl → 2Ag + Cl2
(c) ZnCO3 → ZnO + CO2
(d) H2(g) + Cl2(g) → 2HCl(g)

Answer

Answer: c


38. The following reaction is an example of a
4NH3(g) + 5O2(g) → 4NO(g) + 6H2O(g)
(i) displacement reaction
(ii) combination reaction
(iii) redox reaction
(iv) neutralisation reaction [NCERT Exemplar Problems]
(a) (i) and (iv)
(b) (ii) and (iii)
(c) (i) and (iii)
(d) (iii) and (iv)

Answer

Answer: c


39. Which of the following statements about the given reaction are correct ?
3Fe(s) + 4H2O(g) → Fe3O4(g) + 6H2(g)
(i) Iron metal is getting oxidised
(ii) Water is getting reduced
(iii) Water is acting as reducing agent
(iv) Water is acting as an oxidising agent [NCERT Exemplar Problems]
(a) (i), (ii) and (iii)
(b) (iii) and (iv)
(c) (i), (ii) and (iv)
(d) (ii) and (iv)

Answer

Answer: c


40. Which of the following are exothermic processes?
(i) Reaction of water with quick lime
(ii) Dilution of an acid
(iii) Evaporation of water
(iv) Sublimation of camphor (crystals) [NCERT Exemplar Problems]
(a) (i) and (ii)
(b) (ii) and (iii)
(c) (i) and (iv)
(d) (iii) and (iv)

Answer

Answer: a

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