tests for ions

Question 1

tests for cations

Answer 1

1. flame test
2. use sodium hydroxide solution
3. use ammonia solution

Question 2

how to carry out the flame test

Answer 2

nichrome wire is dipped into concentrated hydrochloric acid and then into the sample.
it is them placed into a blue flame and the colour is observed

Question 3

what colour is lithium ions in the flame test

Answer 3

crimson

Question 4

what colour is sodium ions in the flame test

Answer 4

yellow/orange

Question 5

what colour is potassium ions in the flame test

Answer 5

lilac

Question 6

what colour is calcium ions in the flame test

Answer 6

brick red

Question 7

what colour is copper (II) ions in the flame test

Answer 7

blue-green/ green-blue

Question 8

definition of a precipitate

Answer 8

a solid produced in a solution during a reaction

Question 9

zinc, observation when sodium hydroxide is added

Answer 9

white precipitate which dissolves in excess to form a colourless solution

Question 10

aluminium, observation when sodium hydroxide is added

Answer 10

white precipitate which dissolves in excess to form a colourless solution

Question 11

magnesium, observation when sodium hydroxide is added

Answer 11

white precipitate which does not dissolve in excess

Question 12

copper (II), observation when sodium hydroxide is added

Answer 12

blue precipitate which doesn’t dissolve in excess

Question 13

iron (II), observation when sodium hydroxide is added

Answer 13

green precipitate which does not dissolve in excess

Question 14

iron (III), observation when sodium hydroxide is added

Answer 14

brown precipitate which does not dissolve in excess

Question 15

zinc, observation when ammonia solution is added

Answer 15

white precipitate which dissolves in excess to form a colourless solution

Question 16

aluminium, observation when ammonia solution is added

Answer 16

white precipitate which does not dissolves in excess

Question 17

magnesium, observation when ammonia solution is added

Answer 17

white precipitate which does not dissolves in excess

Question 18

copper (II), observation when ammonia solution is added

Answer 18

blue precipitate which dissolves in excess to form a deep blue solution

Question 19

iron (II), observation when ammonia solution is added

Answer 19

green precipitate which does not dissolve in excess

Question 20

iron (III), observation when ammonia solution is added

Answer 20

brown precipitate which does not dissolve in excess

Question 21

tests for anions

Answer 21

1. test for halide ions
2. test for sulfate ions

Question 22

how to test for sulfate ions

Answer 22

• add barium chloride solution
• a white precipitate forms (if a sulfate ions are present)

Question 23

how to test for halide ions

Answer 23

• add silver nitrate solution
• a precipitate will form. the precipitates formed are silver halides

Question 24

observations when silver nitrate solution is added to different halides: chloride

Answer 24

white precipitate
AgCl

Question 25

observations when silver nitrate solution is added to different halides: bromide

Answer 25

cream precipitate AgBr

Question 26

observations when silver nitrate solution is added to different halides: iodide

Answer 26

yellow precipitate AgI

Question 27

apart from the flame test, the compounds must be in ______________

Answer 27

solution

Question 28

if you are asked to describe a test what should u state first

Answer 28

the solid needs to be dissolved in distilled water

Question 29

ionic equation for the reaction of iron (II) ions reacting with hydroxide ions to form solid iron (II) hydroxide

Answer 29

Fe 2+(aq) + 3OH- (aq) -> Al(OH)3 (s)

Question 30

ionic equation for the reaction of aluminium ions reacting with hydroxide ions to form solid aluminium hydroxide

Answer 30

Al 3+ (aq) + 3OH- (aq) -> Al(OH)3 (s)

Question 31

name the ion identified using barium chloride solution. state the observation and write an ionic equation

Answer 31

sulfate white ppt Ba 2+ (aq) + SO4 2- (aq) -> BaSO4 (aq)