Halogens Flashcards Preview

Chemistry, Module 3 OCR > Halogens > Flashcards

Flashcards in Halogens Deck (14)
Loading flashcards...
1
Q

State of bromine

A

Red/ brown liquid

2
Q

State of iodine

A

Black solid

3
Q

Cl2 when in
water
cyclohexane

A

Pale green

4
Q

Br2 when in
Water
Cyclohexane

A

Orange

5
Q

I2 when in
Water
Cyclohexane

A

Brown

Purple

6
Q

Purpose of chlorine in water purification

A

Kills pathogen to avoid disease

Chlorine reacts with water to form acidic solution that kills pathogens

7
Q

Chlorine and water reaction

A

Forms

hydrochloric acid

Chloric acid (HOCl)

8
Q

Why is Cl2 reaction with H2O disproportionation reaction

A

Chlorine is both oxidised and reduced

Oxidised on HOCl
Reduced in HCl

9
Q

Risks of using chlorine to purify water

A

Gas is toxic

Chlorinated hydrocarbon may form which are carcinogenic

10
Q

Benefits of Chlorine purifying water

A

Kills many harmful microorganisms

Reduces rates of waterborne disease; cholera and typhoid

11
Q

How is bleach created

A

Cl2 and cold dilute NaOH

Forms NaOCl and NaCl

NaOCl is the bleach

12
Q

State and colour of chlorine

A

Yellow/ green gas

13
Q

Describe trend in boiling point down the group.

A
  • Increases
  • Greater amount of electrons down the group means that there are stronger London forces between the molecules
  • Thus requiring greater energy to break the attraction
14
Q

Describe the test for halide ions.

Including ionic equation.

A
  • Add AgNO3 to unknown solution
  • Precipitation reaction will form a Silver halide
  • X- + Ag+ = AgX
  • Colour of the ppt indicates the type of halide ion;
    White- Chloride
    Cream- Bromide
    Yellow- Iodide

The further distinguish, NH3 is added;
Dilute NH3 dissolves Cl- but not Br-
Concentrated NH3 dissolves Br-