Analysis of positive ions

Question 1

What colour flames do lithium compounds exhibit?

Answer 1

crimson

Question 2

What colour flames do sodium compounds exhibit?

Answer 2

yellow

Question 3

What colour flames do potassium compounds exhibit?

Answer 3

lilac

Question 4

What colour flames do calcium compounds exhibit?

Answer 4

red

Question 5

What colour flames do barium compounds exhibit?

Answer 5

green

Question 6

What colour precipitates do copper ions produce with sodium hydroxide?

Answer 6

blue

Question 7

What colour precipitates do iron2+ ions produce with sodium hydroxide?

Answer 7

dark green

Question 8

What colour precipitates do iron3+ ions produce with sodium hydroxide?

Answer 8

brown

Question 9

What colour precipitates do aluminium ions produce with sodium hydroxide?

Answer 9

white

Question 10

What colour precipitates do magnesium ions produce with sodium hydroxide?

Answer 10

white

Question 11

What colour precipitates do calcium ions produce with sodium hydroxide?

Answer 11

white

Question 12

What happens to aluminium’s precipitate when excess sodium hydroxide is added?

Answer 12

it redissolves and becomes clear and colourless

Question 13

What happens in a flame photometer?

Answer 13

A metal ion is burnt and the light intensity and wavelength is measured. The metal ion can be identified and also the amount of the metal ion present.