Halogens

Question 1

Trend in boiling points and why

Answer 1

Increase down the group because stronger van der waals forces as larger mr

Question 2

trend in electronegativity and why

Answer 2

decreases down the group because more electron shielding so less strong attraction to the valence electrons

Question 3

reactivity trend and why

Answer 3

less reactive down the group because halogens gain an electron when reacting and thus larger atomic radius and more electron shielding will make it harder to gain electron

Question 4

oxidising power trend

Answer 4

less oxidising down the group

Question 5

ionic equation of chlorine and bromine displacement reaction

Answer 5

Cl2 + 2Br- = 2Cl- + Br2

Question 6

chlorine + potassium bromide colour change

Answer 6

colourless to orange

Question 7

chrorine + potassium iodide colour change

Answer 7

colourless to brown solution

Question 8

bromine water + potassium iodide colour change

Answer 8

orange to brown

Question 9

F2 colour and state

Answer 9

pale yellow gas

Question 10

chlorine colour and state

Answer 10

pale green gas

Question 11

bromine colour and state

Answer 11

red/brown liquid, brown/orange gas

Question 12

iodine colour and state

Answer 12

grey solid and purple gas

Question 13

what happens when you mix chlorine and cold, dilute sodium hydroxide + equation

Answer 13

2NaOh + Cl2 = NaClO + NaCl + H2O
Makes bleach
disproportionation reaction as chlorine is oxidised and reduced simultaneously

Question 14

chlorine + water equation

Answer 14

Cl2 + H2O =(reversible) HClO + HCl

Question 15

chlorine + water in sunlight

Answer 15

2CL2 + 2H2O = 4H+ + 4Cl- + O2

Question 16

trend in reducing power and why

Answer 16

increases down the group because more electron shielding so easier to lose electron

Question 17

NaF + sulfuric acid equation and observation

Answer 17

NaF + H2SO4 = NaHSO4 + HF misty fumes produced

Question 18

NaCl + sulfuric acid equation and observation

Answer 18

NaCl + H2SO4 = NaHSO4 + HCl misty fumes produced

Question 19

NaBr and sulfuric acid two equations and observations and explanation

Answer 19

NaBr + H2SO4 = NaHSO4 + HBr
2HBr + H2SO4 = Br2 + SO2 = 2H2O

redox equation, misty fumes first reaction, orange fumes second reaction as bromine is better reducing agent so reacts further

Question 20

NaI and sulfuric acid four equations and observations and explanation

Answer 20

NaI + H2SO4 = NaHSO4 + HI
2HI + H2SO4 = I2 + SO2 + 2H2O
6HI + H2SO4 = 3I2 + S + 4H2O
8HI + H2SO4 = 4I2 + H2S + 4H2O
gas produced and grey iodine solid

Question 21

what do you add to test for halide ions and why

Answer 21

dilute nitric acid to remove unwanted ions then add silver nitrate solution

Question 22

fluoride and silver nitrate observation

Answer 22

no precipitate

Question 23

chloride and silver nitrate

Answer 23

white precipitate

Question 24

bromide and silver nitrate

Answer 24

cream precipitate

Question 25

iodide and silver nitrate

Answer 25

yellow precipitate

Question 26

chloride and ammonia solution

Answer 26

white precipitate, dissolves in DILUTE NH3

Question 27

bromide and ammonia solution

Answer 27

cream precipitate, dissolves in CONCENTRATED NH3

Question 28

iodide and ammonia solution

Answer 28

yellow precipitate, INSOLUBLE in any ammonia solution