Chemical Reactions


Electrolysis of water is a decomposition reaction. The mole ratio of hydrogen and oxygen gases liberated during electrolysis of water is

  1. 1:1
  2. 2:1
  3. 4:1
  4. 1:2
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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?

  1. Displacement reaction
  2. Precipitation reaction
  3. Combination reaction
  4. Double displacement reaction

Select the correct option:

  1. (i) only
  2. (ii) only
  3. (iv) only
  4. (ii) and (iv)
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A dilute ferrous sulphate solution was gradually added to the beaker containing acidified permanganate solution. The light purple colour of the solution fades and finally disappears. Which of the following is the correct explanation for the observation?

  1. KMnO4 is an oxidising agent, it oxidises FeSO4
  2. FeSO4 acts as an oxidising agent and oxidises KMnO4
  3. The colour disappears due to dilution; no reaction is involved
  4. KMnO4 is an unstable compound and decomposes in presence of FeSO4 to a colourless compound.
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Three beakers labelled as A, B and C each containing 25 mL of water were taken. A small amount of NaOH, anhydrous CuSO4 and NaCl were added to the beakers A, B and C respectively. It was observed that there was an increase in the temperature of the solutions contained in beakers A and B, whereas in case of beaker C, the temperature of the solution falls. Which one of the following statement(s) is (are) correct?

  1. In beakers A and B, exothermic process has occurred.
  2. In beakers A and B, endothermic process has occurred.
  3. In beaker C exothermic process has occurred.
  4. In beaker C endothermic process has occurred.

Select the correct option:

  1. (i) only
  2. (ii) only
  3. (i) and (iv)
  4. (ii) and (iii)
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Which of the following are exothermic processes?

  1. Reaction of water with quick lime
  2. Dilution of an acid
  3.  Evaporation of water
  4. Sublimation of camphor (crystals)

Select the correct option:

  1. (i) and (ii)
  2. (ii) and (iii)
  3. (i) and (iv)
  4. (iii) and (iv)
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Which of the following is not a physical change?

  1. Boiling of water to give water vapour
  2. Melting of ice to give water
  3. Dissolution of salt in water
  4. Combustion of Liquefied Petroleum Gas (LPG)
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