Testing for Cations

Why can't you use a flame test to distinguish between silver and lead?

• silver is colourless

• lead is toxic

• they are the same colour

• both 1 & 2 are correct

A white precipitate forming when ammonia is added to an unknown light blue precipitate indicates the presence of....

• copper

• magnesium

• barium

• silver

A cobalt blue precipitate forming when ammonia is added to an unknown light blue precipitate indicates the presence of....

• silver

• lead

• magnesium

• copper

Ammonia can be added to a light blue precipitate to distinguish between....

• magnesium & silver

• magnesium & copper

• copper & silver

• silver & lead

A light blue precipitate formed when sodium hydroxide is added to an unknown solution indicates the presence of.....

• barium

• calcium

• copper

• iron(II)

A green precipitate formed when sodium hydroxide is added to an unknown solution indicates the presence of.....

• iron(III)

• calcium

• copper

• iron(II)

An orange-brown precipitate formed when sodium hydroxide is added to an unknown solution indicates the presence of.....

• iron(III)

• calcium

• copper

• iron(II)

Dilute sodium hydroxide can be added to an unknown solution to indicate the presence of....

• iron(II)

• iron(III)

• copper

• all of the above

Potassium thiocyanate added to an orange-brown precipitate will form a blood red precipitate if which ion is present?

• iron(II)

• barium

• lead

• iron(III)

Tags

NGSS.HS-PS1-1

Sodium fluoride added to a sample will form a white precipitate if which ion is present?

• calcium

• barium

• silver

• lead