C2 identifying the ions in an ionix compound using flame tests

Ionic compounds are made of what

Cation and anion

Cation have characteristic colour when held in flame

Method

1. Take a piece of nichrome wire with a loop at one end.

2. Dip the loop in the concentrated hydrochloric acid and place in the hot blue flame of the Bunsen burner.

3. Repeat until the flame is no longer coloured, i.e. impurities are removed.

4. Dip the clean nichrome wire in concentrated hydrochloric acid and the wire onto the solid ionic compound which is sitting in a watch glass.

5. Hold the loop with the solid ionic compound in the hottest part of the flame and record the characteristic colour.

6. Repeat for all the solid ionic compounds available, cleaning the wire loop each time.

Sodium observation

Yellow/orange

Calcium observation

Brick red

Potassium observation

Lilac

Copper observetion

Blue-green

Lithium observation

Crimson