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Questions 6.3.2

Write equations to represent the following reactions of carbon (IV) oxide

  1. Carbon (IV) oxide slightly dissolves in water to form carbonic acid (H2CO3) which is a weak acid and turns blue litmus pink.

    2. Equation:

  2. Carbon (IV) oxide reacts with calcium hydroxide solution to form a white precipitate, which is calcium carbonate.

    3. Equation:

  3. Excess of carbon (IV) oxide causes the carbonate to dissolve by forming calcium hydrogencarbonate, Ca(HCO3)2. Water also takes part in this reaction.

    4. Equation:

  4. In the same manner, carbon (IV) oxide reacts with sodium hydroxide solution to form sodium carbonate (Na2CO3). But, unlike calcium carbonate, this is soluble; so it is in solution.

    5. Equation:

  5. With excess of carbon (IV), sodium carbonate (Na2CO3) reacts to form sodium hydrogencarbonate solution (NaHCO3). Water also takes part in this reaction.

    6. Equation:

  6. Carbon (IV) oxide reacts with burning magnesium to form a white solid, which is magnesium oxide, and carbon as black specks.

    7. Equation:




Answers to Questions 6.3.2

  1. H2O(l)   +   CO2(g)   ⟶   H2CO3(aq)

  2. Ca(OH)2(aq)   +   CO2(g)   ⟶   CaCO3(s)   +   H2O(l)

  3. CaCO3(s)   +   CO2(g) + H2O(l)   ⟶   Ca(HCO3)2(aq)

  4. 2NaOH(aq)   +   CO2(g)   ⟶   Na2CO3(aq)   +   H2O(l)

  5. Na2CO3(aq)   +   CO2(g)   +   H2O(l)   ⟶   2NaHCO3(aq)

  6. 2Mg(s)   +   CO2(g)   ⟶   2MgO(s)   +   C(s)