21 Chemistry -- Non-Metals: Halogens

Why can't HBr and HI be prepared by treating conc.H2SO4 with bromide and iodide?

1 Answers

HBr and and HI can't be prepared by treating conc. H₂ SO₄ with Bromide and Iodide as HBr and HI are strong reducing agents and they reduce H₂SO₄ into SO₂and themselves into Br₂ and I₂ respectively.

i.e.

2NaBr+H₂SO₄-----------_heat--------------> Na₂SO₄+2HBr

2HBr +H₂SO₄----------------------------> SO₂+2H₂O+Br₂

2NaI+H₂SO₄-----------_heat--------------> Na₂SO₄+2HI

2HI+H₂SO₄----------------------------> SO₂+2H₂O+I₂

Why are halogens not found in a free state in nature ?

Halogens have high electron affinity thus, they easily react with other elements to form compounds. They are just short of one electron to attain stable electronic configuration. Hence, there are not found in a free state in nature.

Give any one chemical reaction to prepare chlorine gas from hydrochloric acid.

By the reaction of Hydrochloric acid and Manganese dioxide.

2HCl + MnO₂ --> MnCl₂ + H₂O + [O]

2HCl + [O] --> H₂O+ Cl₂

4HCl +MnO₂-->MnCl₂+ 2H₂O +Cl₂

Give a chemical reaction to show the oxidizing action of chlorine.

How would you obtain bromine from HBr?

Why HI cannot be prepared by the action of conc. H2SO4 on NaI ?

Describe the manufacture of bromine from carnallite.

How would you test the presence of Cl_ ion in the aqueous solution?

Compare and contrast the properties of HCl, HBr, and HI.

Why HBr and HI cannot be prepared by the action of conc. H,SO, on bromide and iodiderespectively? Suggest alternative methods for the preparation of HBr and HI. How would youtest chloride ion in th...

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