Group 7-Halogens

Fluorine gas colour

Yellow

Test for ammonia

EQ

Add NaOH

Hold damp red litmus paper at the mouth of the tube

9o8

Test for carbonate what acids can you add

EQ

Nitric acid

Hydrochloric acid

Test for sulfate ions

EQ

Add barium chloride

Sulfate gives white precipitate

What do you have to remember when doing half equations?

EQ

BALANCE FIRST

With both compounds on either side

Not last or whole equation is wrong

Similarity between sodium chlorides reaction with concentrated sulfuric aid and sodium bromides

EQ

Both form hydrogen halides

Difference between sodium chlorides reaction with concentrated sulfuric aid and sodium bromides

EQ

Bromide ions reduce sulfur in sulfuric acid

Oxidising agent definition

EQ

Electron acceptor

Give an equation to show the reaction between iodide ions and concentrated sulfuric acid to form the yellow solid

EQ

What is a sulfur containing foul smell in gas?

EQ

Hydrogen sulfide

Name the compound/element that is a yellow solid

EQ

Sulfur

Explain this observation

Effervescence when adding sodium carbonate

EQ

Shows contains hydrogen ions

So it is acidic

If a white precipitate is formed when adding silver nitrate to a sample what does that show

EQ

Chloride ions are present

Second mass is smaller/mass after step 4 is smaller that mass after step 2

AgCl dissolves in dilute ammonia

State why the amount of chlorine added to water must be controlled

EQ

Poisonous

Give an equation for the reaction of chlorine with water to form a solution containing 2 acids

EQ

Observation when solid iodine is formed in a solution as a ppt

EQ

Brow solution

Black solid

Give an equation for the formation of sulfur dioxide when concentrated sulfuric acid is added to sodium iodide

EQ

Give an equation for the formation of hydrogen sulfide when concentrated sulfuric acid is added to sodium iodide

EQ

Observation of sodium fluoride with acidified silver nitrate

EQ

No visible reaction

Solution remains colourless

Ionic equation for the formation of sodium carbon dioxide

EQ

True or false

Sodium bromide forms bromine when added to concentrated sulfuric acid

EQ

True

True or false

Boiling points decreases from HCl to HI

False

Reducing ability increases down the group so is bromine a better oxidising agent or chlorine

EQ

Bromine

True or false

Chlorine can react with water to form an alkaline solution

False

Which is the best reducing agent

Cl2

Cl-

I2

I-

I-

Which species is the best oxidising agent

Cl2

Cl-

Br2

Br-

EQ

Cl2

Sodium chloride with acid base reaction-only one sulfur product

Sodium iodide-3 sulfur products

Sodium bromide- 2 sulfur products-1 redox reaction-with sulfur

What are the main products of these with sulfuric acid

EQ

H2

What can iodine reduce h2SO4 t?

EQ

Hydrogen sulfide

Sulfur

Sodium hydrogen sulfate

Dilute sulfuric acid with sodium iodide non redox reaction products

EQ

Sodium hydrogen sulfate

Iodine water

Concentrated sulfuric acid+ sodium iodide products

EQ

Sodium hydrogen sulfate

HI -hydrogen iodide

Concentrated sulfuric acid+ sodium chloride

EQ

HCl

Sodium hydrogen sulfate

Concentrated sulfuric acid+ sodium bromide products

EQ

HBr

Sodium hydrogen sulfate

Why does sodium fluoride not react with an acid?

EQ

It is a dilute not concentrated acid

Must be concentrated to produce F2

Is this too much or less for a boiling tube?

EQ

Too much so use large beaker

How do you maximise AgCl production?

EQ

Use excess HCl

What does decanting mean

EQ

A wet solid

Or some solid lost

Method of filtration

EQ

Filter

Wash

Dry

Lattice so there are —— strong bonds

EQ

Many

Disadvantage of treating water with chlorine

EQ

Some people find the taste unpleasant

Why does sodium bromide react with concentrated sulfuric acid in a different way to sodium chloride

EQ

Bromine ions are bigger than Cl- ions

How do you dissolve AgCl

EQ

Add excess dilute ammonia

Formula for dissolving silver chloride in dilute ammonia

EQ

AgCl+NH3 —> Ag(NH3)2 ^+ + Cl-

Ionic equation for the reaction between chlorine and cold dilute sodium hydroxide solution

EQ

Cl2 + 2HO- —> OCl- + Cl- + H2O

Equation for sodium chloride and concentrated sulfuric acid

EQ

NaCl +H2SO4 —>NaHSO4 + HCl

What is the role of sulfuric acid in the reaction fo sodium chloride with sulfuric acid

EQ

Proton donor

What is the role of sulfuric acid in the reaction of sodium bromide with concentrated sulfuric acid

EQ

Oxidising agent

If you have a solid sample and have to conduct tests on it what is the first thing you have to do?

EQ

Add water to make it a solution

What test would you do for sodium carbonate?

EQ

Add an acid

Fizzes

What happens if you add an acid or silver nitrate to sodium fluoride?

EQ

No change

What is formed when a metal carbonate reacts with a base?

EQ

Salt

Carbon dioxide

Water

What is produced in the redox reaction of concentrated sulfuric acid and sodium iodide?

EQ

Sulfur

Hydrogen sulfide

iodine

Give an equation for the reaction of solid bromide with concentrated sulfuric acid to form bromine

EQ

NaBr + H2SO4 —>SO2 +Br2 +Na2SO4 + H2O

Whenever bromine is formed in a product what colour is the solution

EQ

Orange brown solution

Explain how the forces between molecules of chlorine arise

EQ

Movement of electrons in one molecule

Induces a dipole in a neighbouring molecule

Temporary dipoles attract

Give an equation for the reaction of chlorine with water

EQ

Cl2 +H2O —>HCl +O2

Give an equation for the reaction of cold aqueous sodium hydroxide in the manufacture of bleach

EQ

Cl2 + NaOH —> NaCl +NaClO +H2O

What colour is the product when bromine the product itself is formed along with a salt

EQ

Brown solution

D

Iodide solution brown as well

A

Give an equation for the reaction of solid sodium bromide with concentrated sulfuric acid

EQ

NaBr + H2SO4 >Na2SO4 +SO2+Br2 +H2O

Why is HNO3 added to test for halides?

EQ

Removes carbonate ions that may give other precipitates with AgNO3

Why is AgNO3 added to test for halides?

EQ

Produces precipitates with chloride

Why is dilute aqueous ammonia added in halide test between 2 halides?

EQ

It dissolves one of them leaving the other

Formula of silver chloride with ammonia

EQ

Explain why chlorine is added to water even though it is toxic

EQ

Health benefit outweighs risk

Equation for reaction of chlorine with cold water

EQ

Bottom EQ

Suggest why an excess of silver nitrate is used in test

EQ

To ensure that all the halide ions are removed from the solution

State what is observed when silver nitrate solution is added to sodium fluoride solution

EQ

Colourless solution

State one observation when solid sodium chloride reacts with concentrates sulfuric acid

EQ

Misty

Role of chloride ions in the reaction of sodium chloride with concentrated fluoride solution
EQ

Proton accept on

Redox equation of sodium bromide with concentrated sulfuric acid

EQ

NaBr +H2SO4 —>Na2SO4 +Br2 +SO2 +H2O

What are the major products formed when chlorine reacts with cold dilute aqueous sodium hydroxide?

EQ

NaCl and NaClO

What products are for me when iodine reacts with sulfuric acid

H2S

SO4 2-

S

SO2

What are the products of Br- and sulfuric acid

Hydrogen bromide and sulfur dioxide

What is formed when chlorine reacts with water

HClO

HCl

Chlorine gas colour

Green

Bromine gas colour

Red brown

Iodine gas colour

Grey

Describe boiling points down group 7.

Increases down the groups

Why does the boiling point increase down the group?

Increases strength of VDW as size and Mr of molecules increases

Physical state of fluorine

Gas

Physical state of chlorine

Gas

Physical state of bromine

Liquid

Physical state of iodine

Solid

Trend in electronegativity down the group

Decreases down the group

Why does electronegativity decrease down the group?

Outer electrons are further from the nucleus and are more shielded as they have more inner electrons

Are all halogens oxidising agents?

Yes

Why are all halogens oxidising agents?

They gain an electron

What happens when chlorine is added to potassium chloride solution?

No reaction

What happens when chlorine is added to potassium bromide?

Orange solution

Because Br2 is formed

What happens when chlorine is added to potassium iodide?

Brown solution

Because iodine is formed

What happens when bromine is added to potassium chloride?

No reaction

What happens bromine is added to potassium bromide?

No reaction

What happens when bromine is added to potassium iodide?

Brown solution

Iodine

What happens when iodine is added to potassium chloride?

No reaction

What happens when iodine is added to potassium bromide?

No reaction

What happens when potassium iodide is added to iodine?

No reaction