RP: Flame Test

What is the aim of the flame-test practical?

To identify metal ions from their characteristic flame colours.

What apparatus is required for a flame test?

Bunsen burner, wire loop, hydrochloric acid and metal salt samples.

What is the first step in a flame test?

Clean the wire loop using hydrochloric acid.

What should be done after cleaning the wire loop?

Heat it in the blue Bunsen flame until no colour is observed.

How is the sample introduced into the flame?

Dip the clean loop into the metal salt sample and place it in the flame.

What should be recorded?

The observed flame colour.

Why must the loop be cleaned between samples?

To prevent cross-contamination.

Why is a blue flame used?

It is hot and less luminous, allowing flame colours to be observed more clearly.

How can the accuracy of identifying an unknown ion be improved?

Compare its flame colour with known reference samples.

Why might flame tests be unreliable for mixtures?

One flame colour may mask another.

What is one improvement over ordinary flame tests?

Use flame emission spectroscopy to identify characteristic emission wavelengths.