topic 4b: halogens

Question 2

f2 at room temperature

Answer 2

pale yellow gas

Question 3

cl2 at room temperature

Answer 3

pale green gas

Question 4

br2 at room temperature

Answer 4

red liquid with orange vapours

Question 5

i2 at room temperature

Answer 5

grey solid
sublimes to purple gas

Question 6

melting point and boiling point down group 7

Answer 6

• INCREASES
• more electrons
• stronger london forces
• more energy required to separate molecules

Question 7

electronegativity down group 7

Answer 7

• decreases
• atomic radii increase
• more shells, more shileding
• greater distance from positive nucleus to electrons
• weaker ESA

Question 8

oxidising strength down group

Answer 8

DECREASES. ie fluroine is strongest oxidising agent

Question 9

cl displaces

Answer 9

br and i

Question 10

br displaces

Answer 10

i only

Question 11

i displaces

Answer 11

NO ONE
- weakest oxidising agent

Question 12

colour of solution when CHLORINE is displaced

Answer 12

colourless

Question 13

colour of organic solvent when chlorine is displaced

Answer 13

colourless

Question 14

colour of solution when bromine is displaced

Answer 14

yellow

Question 15

colour of solution when iodine is displaced

Answer 15

brown solution

Question 16

colour of orhanic solution when bromine dispalced

Answer 16

yellow

Question 17

colour of organic solvent when iodine displaced

Answer 17

PURPLE

Question 18

iodine oxidising power

Answer 18

WEAKEST

Question 19

cl2 + h2o

Answer 19

hcl + hclo

Question 20

chlorine with water tests

Answer 20

• ## damp blue litmus / UI goes red (and then litmus bleached)

Question 21

cl2 + COLD DILUTE NaOH

Answer 21

nacl + naclo + h2o

Question 22

cl2 HOT CONCENTRATED NaOH

Answer 22

3cl2 + 6naoh = 5nacl + naclo3 +3h2o

Question 23

group 1 fluorides and chlorides + acid

Answer 23

• acid base reaction
• h2so4 not a strong enough oxidising agent

Question 24

reactions of group 1 halides + acids the halides act as

Answer 24

reducing agents therefore NaI is the strongest reducing agent

Question 25

effect of too much HClO

Answer 25

• corrosive, toxic etc

Question 26

test for halide

Answer 26

• nitric acid
• silver nitrate
• obserbe ppt

Question 27

purpose of adding nitric acid in the test for halides

Answer 27

react with any carbonates to prevent formation of silver carbonate ppt

Question 28

halid test : chrlodie

Answer 28

white ppt (agcl)

Question 29

halide test: bromide

Answer 29

cream ppt (AgBr)

Question 30

halide test: iodide

Answer 30

yellow ppt (AgI)

Question 31

AgCl + dilute ammonia

Answer 31

dissolves, colourless soludtion

Question 32

AgBR + dilute ammonia

Answer 32

nothing
in CONC ammonia, dissolves to form colourless solution

Question 33

hydrogen halide + ammonia

Answer 33

ammonium halide
white smoke

Question 34

NaCl + h2so4

Answer 34

= Na2SO4 + HCl

Question 35

NaF + H2SO4

Answer 35

= Na2SO4 (solid) + HF (gas)

Question 36

HX gas observation

Answer 36

steamy fumes

Question 37

NaBr + H2SO4

Answer 37

• br- strong reducing agent
  1. 2NaBr + H2SO4 = Na2SO4 + 2HBr
  2. 2Hbr + H2SO4 = Br2 + SO2 + 2H2O

Question 38

NaI + H2SO4

Answer 38

• I- strongest reducing agent
  1. NaI + H2SO4 = Na2SO4 + HI
  2. HI + H2SO4 = H2O + SO2 + I2
  3. 6HI + SO2 = H2S + 3I2 + 2H2O

Question 39

bromine issue

Answer 39

corrosive
wear gloves

Question 40

OVERALL NaBr + H2SO4

Answer 40

2NaBr + 2H2SO4 = Br2 + Na2SO4 + SO2 + 2H2O

Question 41

organic layer in the halide displacement

Answer 41

X2 dissolved in cyclohexane

Question 42

what type of reaction is NaCl or NaF and h2so4

Answer 42

ACID BASE
not redox as nothing changes oxidation state !!!!!!1

Question 43

agbr + CONC ammonia give the complex ion formula

Answer 43

Ag[NH3]2 +

Question 44

agno3 + f2

Answer 44

no observation as AgF is soluble

Question 45

in a separating funnel, the organic layer is

Answer 45

ON TOP
aqueous layer underneath

Question 46

hydrogen halides solubility

Answer 46

siluble