module 3 tests

Question 1

Chlorine in water

Answer 1

pale green

Question 2

Bromine in water

Answer 2

orange

Question 3

Iodine in water

Answer 3

brown

Question 4

Iodine in cyclohexane

Answer 4

violet

Question 5

role of cyclohexane?

Answer 5

makes the colour change more visible to see

Question 6

F2 colour and state

Answer 6

pale yellow and gas

Question 7

Cl2 colour and state

Answer 7

pale green gas

Question 8

Br2 colour and state

Answer 8

red-brown liquid

Question 9

I2 colour and state

Answer 9

shiny grey-black solid

Question 10

carbonate test

Answer 10

reacts with acid to produce carbon dioxide

- bubble gas produced through limewater and solution should turn from white to milky

Question 11

sulfate test

Answer 11

add BaCl and a white precipitate should form

Question 12

chloride test

Answer 12

add silver nitrate and should turn white

Question 13

bromide test

Answer 13

add silver nitrate and should turn creamy

Question 14

iodide test

Answer 14

add silver nitrate and should turn yellow

Question 15

what order should the tests be done in?

Answer 15

1. carbonate
2. sulfate
3. halides

Question 16

why is there a specific order?

Answer 16

the carbonate test will only produce bubbles if there is a carbonate ion (it cannot if it is a sulfate or halide)

adding BaSO4 to a sulfate and carbonate solution produces a white precipitate. therefore by doing the carbonate test first you can only eliminate the carbonate ion and then recognise whether a sulfate ion is present

adding silver nitrate to a carbonate and sulfate solution also produces precipitates. therefore by doing those first you can eliminate them and focus on the halides

Question 17

ammonium ions test

Answer 17

add sodium hydroxide
warm the solution
use litmus paper and should turn blue

Question 18

which halide is insoluble in ammonia?

Answer 18

iodide