Group 7, the Halogens: Uses of Chlorine and Chlorate(I) Flashcards
What type of reaction occurs when chlorine reacts with cold water or sodium hydroxide?
- Disproportionation reaction
Define the term disproportionation
- A reaction in which the same element is simultaneously oxidised and reduced
Give the symbol equation for the reaction between chlorine and cold water, including state symbols
- Cl2 (g) + H2O (l) ⇌ 2H+ (aq) + Cl- (aq) + ClO- (aq)
Explain how the reaction between chlorine and cold water is a disproportionation reaction
- Cl2 (g) + H2O (l) ⇌ 2H+ (aq) + Cl- (aq) + ClO- (aq)
- Cl2 OS is 0
- Cl- OS is -1
- ClO- OS is +1
- Cl is both oxidised and reduced
Give the symbol equation for the reaction between chlorine and water in sunlight, including state symbols
- 2Cl2 (g)+ 2H2O (l) → 4HCl (aq) + O2 (g)
Why is chlorine an effective water treatment?
- Chlorate(I) ions kill bacteria
What is the downside of using chlorine to treat water?
- Chlorine is toxic
Why is chlorine still used to treat water?
- The benefits of killing bacteria outweigh the risks of the toxic chlorine
What is produced when chlorine gas is reacted with sodium hydroxide?
- Sodium chlorate(I) solution (NaClO)
- Common household bleach
Give the symbol equation for the reaction between sodium hydroxide and chlorine, including state symbols
- 2NaOH (aq) + Cl2 (g) → NaClO (aq) + NaCl (aq) + H2O (l)
Explain why the reaction between sodium hydroxide and chlorine is a disproportionation reaction
- 2NaOH (aq) + Cl2 (g) → NaClO (aq) + NaCl (aq) + H2O (l)
- Cl2 OS is 0
- NaClO OS is +1
- NaCl OS is -1
- Cl is both oxidised and reduced
What are the uses of sodium chlorate(I) solution?
- Used in water treatment
- Bleach paper and textiles
- Cleaning toilets
