topic 4b: halogens

Question 1

f2 at room temperature

Answer 1

pale yellow gas

Question 2

cl2 at room temperature

Answer 2

pale green gas

Question 3

br2 at room temperature

Answer 3

red liquid with orange vapours

Question 4

i2 at room temperature

Answer 4

grey solid
sublimes to purple gas

Question 5

melting point and boiling point down group 7

Answer 5

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

Question 6

electronegativity down group 7

Answer 6

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

Question 7

oxidising strength down group

Answer 7

DECREASES. ie fluroine is strongest oxidising agent

Question 8

cl displaces

Answer 8

br and i

Question 9

br displaces

Answer 9

i only

Question 10

i displaces

Answer 10

NO ONE
- weakest oxidising agent

Question 11

colour of solution when CHLORINE is displaced

Answer 11

colourless

Question 12

colour of organic solvent when chlorine is displaced

Answer 12

colourless

Question 13

colour of solution when bromine is displaced

Answer 13

yellow

Question 14

colour of solution when iodine is displaced

Answer 14

brown solution

Question 15

colour of orhanic solution when bromine dispalced

Answer 15

yellow

Question 16

colour of organic solvent when iodine displaced

Answer 16

PURPLE

Question 17

iodine oxidising power

Answer 17

WEAKEST

Question 18

cl2 + h2o

Answer 18

hcl + hclo

Question 19

chlorine with water tests

Answer 19

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

Question 20

cl2 + COLD DILUTE NaOH

Answer 20

nacl + naclo + h2o

Question 21

cl2 HOT CONCENTRATED NaOH

Answer 21

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

Question 22

group 1 fluorides and chlorides + acid

Answer 22

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

Question 23

reactions of group 1 halides + acids the halides act as

Answer 23

reducing agents therefore NaI is the strongest reducing agent

Question 24

effect of too much HClO

Answer 24

• corrosive, toxic etc

Question 25

test for halide

Answer 25

- nitric acid - silver nitrate - obserbe ppt

Question 26

purpose of adding nitric acid in the test for halides

Answer 26

react with any carbonates to prevent formation of silver carbonate ppt

Question 27

halid test : chrlodie

Answer 27

white ppt (agcl)

Question 28

halide test: bromide

Answer 28

cream ppt (AgBr)

Question 29

halide test: iodide

Answer 29

yellow ppt (AgI)

Question 30

AgCl + dilute ammonia

Answer 30

dissolves, colourless soludtion

Question 31

AgBR + dilute ammonia

Answer 31

nothing in CONC ammonia, dissolves to form colourless solution

Question 32

hydrogen halide + ammonia

Answer 32

ammonium halide white smoke

Question 33

NaCl + h2so4

Answer 33

= Na2SO4 + HCl

Question 34

NaF + H2SO4

Answer 34

= Na2SO4 (solid) + HF (gas)

Question 35

HX gas observation

Answer 35

steamy fumes

Question 36

NaBr + H2SO4

Answer 36

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

Question 37

NaI + H2SO4

Answer 37

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

Question 38

bromine issue

Answer 38

corrosive wear gloves

Question 39

OVERALL NaBr + H2SO4

Answer 39

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

Question 40

organic layer in the halide displacement

Answer 40

X2 dissolved in cyclohexane

Question 41

what type of reaction is NaCl or NaF and h2so4

Answer 41

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

Question 42

agbr + CONC ammonia give the complex ion formula

Answer 42

Ag[NH3]2 +

Question 43

agno3 + f2

Answer 43

no observation as AgF is soluble

Question 44

in a separating funnel, the organic layer is

Answer 44

ON TOP aqueous layer underneath

Question 45

hydrogen halides solubility

Answer 45

siluble