Chapter 8

Question 1

What is the reaction of adding chlorine to water?

Answer 1

Cl2(aq) +H2O(l) -> H+ (aq) + HClO(aq)

Question 2

What happens when iodine solution is added to a solution of sodium bromide, and why?

Answer 2

No reaction occurs because bromide is more reactive than iodine

Question 3

What is the sequence of tests to analyse an unknown inorganic compound, their formulae, and the positive result

Answer 3

1. Carbonate (add dilute acid- fizzing)
2. Sulfate (Ba²+ - white precipitate)
3. Halides A (Ag+ - precipitate)

Question 4

How do you distinguish between NaCl, NaBr, and NaI?

Answer 4

Add dilute ammonia. If the substrate dissolves, it is NaCl. Add concentrated ammonia. If it dissolves, then it is NaBr. If it does not dissolve in either test, it is NaI

Question 5

What are the colours of the halogen solutions in water?

Answer 5

Cl2- pale green
Br2- orange
I2 -brown

Question 6

What are the colours of the halogen solutions in cyclohexane?

Answer 6

Cl2- pale green
Br2- orange
I2- violet

Question 7

Why are group 2 elements reducing agents

Answer 7

They add electrons to other species

Question 8

State and explain the trend in alkaliniy of the solution formed ehen group 2 oxides are added to water

Answer 8

Group 2 ocides react with water, forming the metal hydroxide. Hydroxide ions in solution cause alkalinity. Down group 2, the solubility of the metal hydroxide increases, increasing the ph and alkalinity

Question 9

State and explain the trend in boiling points of the halogens flourine and iodine

Answer 9

The boiling point increases due to an increase in elecrons down the group. This increases the strength of the london forces and more energy needed to break the intermolecular forces.

Question 10

Write the eqation for the formation of bleach from chlorine gas and a dilute alkaline solution

Answer 10

Cl2 + 2NaOH ->NaClO + NaCl + H2