8C 3 REACTIONS OF HALIDES WITH SULFURIC ACID

What agents do the halogen ions act as in reactions with sulfuric acid?

1. They act as reducing agents.

Describe and explain the trend in oxidizing power and reducing power of halogens and halides respecctively.

1. The oxidizing power of halogens increase from the bottom up.

2. The reducing power of halogens increase from the top to bottom.

3. The reducing power has something to do with the tendency of the halide to form a diatomic molecule, from two anions(halides) releasing two electrons.

4. As we go down a group the elements get bigger( more electrons and inner electron levels), despite higher nuclear charge. It can be easily oxidized. It will have more of a power to reduce others.( loss electrons)

What should we note about sulfuric acid when forming sulfate ions?

1. Sulfuric acid (concentrated) only contains very few ions.

2. It dissociates to form H+ and HSO4-, though the equilibrium of the equation is to the left(H2SO4)

3. The second ionization to produce SO4 2- ions occurs only to a small extent.

When can sulphuric acid act as an oxidizing agent?

1. When concentrated, it ay also act as an acid.

What are the three possible products of sulphuric acid being reduced?

1. Sulfur dioxide

2. Sulfur

3. Hydrogen sulfide

Write down the three half equations of sulfur for the three different products just mentioned.

What pattern can be noticed from the three equations just written?

1. The decrease in oxidation number of sulfur corresponds to the number of Hydrogen ions added.

What happens when concentrated sulfuric acid is added to sodium chloride?

1. Misty fumes will be seen, with hydrogen chloride being formed. HCl

What happens when sodium bromide is added to concentrated sulfuric acid?

1. Three products will be formed HBr(hydrogen bromide), Br2 (bromine), SO2(sulfur dioxide).

2. HBr can be seen as misty fumes.

3. Br2 can be seen as brown fumes.

4. SO2 is a colorless gas with a choking smell.

5. You will see brown fumes of bromine in the test tube.

What happens when concentrated sulfuric acid added to sodium iodide NaI?

1. There will be 5 products, HI(hydrogen iodide), I2 (iodine), SO2 (sulfur dioxide), S (Sulfur), H2S (Hydrogen sulfide).

2. Purple fumes of iodine will be seen in the test tube.

3. Hydrogen iodide(misty fumes)

4. Iodine(purple fumes or black solide)

5. Sulfur dioxide(colorless gas with choking smell)

6. Sulfur(yellow solid)

7. Hydrogen sulfide(colorless gas with rotten egg smell)

Explain what kind of reaction occurs when concentrated sulfuric acid is added to sodium fluoride?

1. Sulfuric acid would act as an acid, not as an oxidizing agent because of fluorine’s low reducing power, it cannot reduce sulfuric acid.