Testing for ions

Question 1

Method for the flame test in testing for ions

Answer 1

dip wire into hydrochloric acid, clean wire by heating it in the flame, re-dip wire into the acid, dip wire into the sample, hold wire in the flame

Question 2

Method for sodium hydroxide test in testing for ions

Answer 2

add sample to a boiling tube, dissolve in 2cm3 of deionised water, add 1cm3 sodium hydroxide, swirl carefully to mix

Question 3

If flame colour is crimson what it the ion

Answer 3

Lithium (LI+)

Question 4

If flame colour is yellow what it the ion

Answer 4

sodium (NA+)

Question 5

If flame colour is lilac what it the ion

Answer 5

potassium (K+)

Question 6

If flame colour is orange-red what it the ion

Answer 6

calcium (Ca2+)

Question 7

If flame colour is green what it the ion

Answer 7

copper (Cu2+)

Question 8

If precipitate colour is blue what it the ion

Answer 8

copper (Cu2+)

Question 9

If precipitate colour is dirty green what it the ion

Answer 9

iron (Fe2+)

Question 10

If precipitate colour is reddish brown what it the ion

Answer 10

iron (Fe2+)

Question 11

If precipitate colour is white what it the ion

Answer 11

magnesium (Mg2+), calcium (Ca2+) or aluminium (Al2+) = add excess as aluminium dissolves in excess

Question 12

How to test for carbon dioxide in testing for ions

Answer 12

add hydrochloric acid, bubble through limewater = white precipitate

Question 13

How to test for chlorine, bromine, iodine in testing for ions

Answer 13

add nitric acid, few drops of silver nitrate = white - chlorine, cream - bromine, yellow - iodine

Question 14

How to test for sulfur dioxide in testing for ions

Answer 14

add hydrochloric acid, few drops if barium chloride = white precipitate