Chlorine and hypochlorite化學問題2

1. A.

(1) is correct.
Aqueous chlorine oxidizes bromide ion to bromine, which dissolves in the organic solvent to form an orange layer.
Cl2(aq) + 2Br-(aq) → 2Cl-(aq) + Br2(aq)
Aqueous chlorine oxidizes iodide ion to iodine, which dissolves in the organic solvent to form a purple layer.
Cl2(aq) + 2I-(aq) → 2Cl-(aq) + I2(aq)

(2) is incorrect.
Both sodium bromide solution and sodium iodide solution do not react with aqueous iodine.

(3) is incorrect.
Both sodium bromide solution and sodium iodide solution do not react with sodium chloride solution.


2. C.

(1) is incorrect.
Both concentrated nitric acid and concentrated sulphuric acid can react with potassium carbonate powder to give colourless bubbles of carbon dioxide.
K2CO3 + 2HNO3 → 2KNO3 + H2O + CO2
K2CO3 + H2SO4 → K2SO4 + H2O + CO2

(2) is correct.
Zinc reacts with concentrated nitric acid to give a brown gas of nitrogen dioxide.
Zn + 4HNO3 → Zn(NO3)2 + 2H2O + 2NO2
Zinc reacts with hot concentrated sulphuric acid to give a colourless gas of sulphur dioxide.
Zn + 2H2SO4 → ZnSO4 + 2H2O + SO2

(3) is correct.
Concentrated nitric does not react with hydrated copper(II) sulphate crystals.
Concentrated sulphuric acid is a dehydrating agent, which changes hydrated copper(II) sulphate crystals from blue to white.
CuSO4•5H2O → CuSO4 + 5H2O