Group 7 - The Halogens

Question 1

Place the halogens F, Cl, Br and I in order of increasing volatility.

Answer 1

I < Br < Cl < F

Question 2

Place the halogens F, Cl, Br and I in order of increasing reactivity.

Answer 2

I < Br < Cl < F

Question 3

What colour solution is formed when iodine dissolves in hexane?

Answer 3

pink/violet

Question 4

What colour would be seen when chlorine water is added to potassium bromide solution?

Answer 4

orange

Question 5

What colour solution is formed when bromine dissolves in hexane?

Answer 5

orange/red

Question 6

Astatine is a halogen. It can be found below iodine in Group 7 of the periodic table.
Write an ionic equation for the reaction between iodine solution and sodium astatide (NaAt).
[1 mark]

Answer 6

I₂ + 2At⁻ → 2I⁻ + At₂

Question 7

The ionic equation below shows the reaction between iodine solution and sodium astatide.
I₂ + 2At⁻ → 2I⁻ + At₂
State which substance is oxidised.
[1 mark]

Answer 7

(sodium) astatide

Question 8

A student has a sample of an aqueous potassium halide solution. She knows it contains either chloride, bromide or iodide ions. The student adds a few drops of aqueous bromine solution to the test tube and a reaction takes place.
Which halide ion is present in the potassium halide solution?
[1 mark]

Answer 8

(potassium) iodide

Question 9

A student has a sample of an aqueous potassium halide solution. She knows it contains either chloride, bromide or iodide ions. The student adds a few drops of aqueous bromine solution to the test tube and a reaction takes place.
What colour will the aqueous solution in the test tube be after the reaction has finished?
[1 mark]

Answer 9

brown