TRIOXOCARBONATE (IV) ACID

H₂CO₃ is formed when CO_2(g) is dissolved in water. H₂CO₃ is a weak dibasic acid. It forms two series of salts:

1. Normal trioxocarbonate (iv)

2. Acidic hydrogen trioxocarbonate (iv)

Normal trioxocarbonate (iv)

Normal trioxocarbonate (iv) may be regarded as salts derived from H₂CO₃ by the complete replacement of the hydrogen by a metal or cationic radical.

EVALUATION

1.  Describe the laboratory preparation of HCO₃^–

2.  Listthe properties of HCO₃^–

GENERAL EVALUATION/REVISION

1. State Boyle’s law and Charles’ law

2. A certain mass of gas occupies 300cm³ at 35^oC. At what temperature will it have its volume reduced by half, assuming its pressure remains constant

3. An enclosed vessel contains 2.8g of nitrogen and 14.2g of chlorine at atmospheric pressure and 0^oC. What will be the partial pressure of nitrogen, if the temperature is raised to 180^oC?

4. A certain mass of hydrogen gas collected over water at 10^oC and 760mmHg pressure has a volume of 37cm³. Calculate the volume when it is dry at s.t.p (saturated vapour pressure of water at 10^oC = 9.2mmHg)

5. State Graham’s law of diffusion

READING ASSIGNMENT

New school chemistry for senior secondary schools by O.Y Ababio page 133-134.

WEEKEND ASSIGNMENT

1. All are decomposed by heat except (a) BaCO₃ (b) CuCO₃ (c) ZnCO₃ (d) Ag₂CO₃

2. The liquid from a bee sting is found to be acidic. Which of the following solutions will neutralize the bee sting? (a) Solution of pH 9 (b) Solution of pH 7 (c) Solution of pH 5

(d) Solution of pH 1

3. What is the IUPAC name of K₄Fe(CN)₆? (a) Potassium hexacyanoferrate (ii) (b) Potassium hexacyanoferrate (iv) (c) Potassium hexacyanoferrate (vi)

(d) Potassium hexacyanoferrate (vii)

4. Which of the following trioxocarbonates (iv) are not decomposed by heat? (a) Calcium and sodium trioxocarbonate (iv) (b) Potassium and zinc trioxocarbonate (iv) (c) Magnesium and potassium trioxocarbonate (iv) (d) Sodium and potassium trioxocarbonate (iv)

5. An aqueous solution of CaCl₂ is (a) acidic solution. (b) alkaline solution (c) a buffer solution    (d) a neutral solution

THEORY

1. State the function of each of the following substances in the laboratory preparation of dry carbon (iv) oxide: (a) potassium hydrogen trioxocarbonate (iv) solution; (b) fused calcium chloride.

2(a) Draw a labelled diagram for the laboratory preparation of dry carbon (iv) oxide. (b) Write a balanced equation for the decomposition of potassium hydrogen trioxocarbonate (iv).