Halogen Reactions

Question 1

Halogen and Cold alkali

Answer 1

X2 + 2NaOH > NaOX + NaX + H2O

X in NaOX = +1
X in NaX = -1

Question 2

Halogen and hot alkali

Answer 2

3X2 + 6NaOH > NaO3X + 5NaX + 3H2O

X in NaO3X = +5 - Been oxidised more
X in 5NaX = -1

Question 3

Chlorine and sodium hydroxide (halogen and cold alkali) make sodium chlorate commonly known as bleach

Answer 3

Cl2 + 2NaOH > NaClO + NaCl + H2O

NaClO = sodium chlorate

Question 4

Chlorine is used to kill bacteria in water

Answer 4

Cl2 + H2O = HCl + HClO
HClO ionises to make chlorate ions (ClO-)
HClO + H2O = H3O+ + ClO-

Question 5

Reaction of KCL with H2SO4

Answer 5

KCL + H2SO4 > KHSO4 + HCL
Not a redox - f and cl aren’t strong enough reducing agents to reduce sulphuric acid
Misty flames as HCl is given off

Question 6

Reaction of KBr with H2SO4

Answer 6

KBr + H2SO4 > KHSO4 + HBr - MISTY FUMES

2HBr + H2SO4 > Br2 + 2H2O + SO2 - CHOKING FUMES

Question 7

Reaction of KI with H2SO4

Answer 7

KI + H2SO4 > KHSO4 + HI - MISTY FUMES
2HI + H2SO4 > I2 + 2H2O + SO2 - CHOKING FUMES
6HI + SO2 > H2S + 3I2 + 2H2O - SMELLS OF EGGS
KI reduces the most - therefore the best reducing agent