Question

A student wants to carry out flame tests on these three chemicals. Describe how to carry out a flame test.

Answer 1

Answer:

Flame test is one of the chemical tests that can be used to identify a metal or metaloid

in an ionic compound.

Explanation:

Flame test is guided by a principle that when an unknown metal is heated, heat of the flame converts the metal ions into atoms which become excited and emit visible light.

To carry out flame test in a laboratory the following instruments are required:

--> a wire loop

--> Bunsen burner

--> the chemical compound under observation

--> protective wears.

The procedure involves the following steps:

--> turn on the Bunsen burner and adjust the barrel of the burner roll the flame is blue.

--> using a clean wire loop deep into a beaker containing hydrochloric acid.

--> to ensure that the loop is clean, it will give the same blue colour of the flame when heated.

--> deep the loop in the acid again and then use it to pick few grains of the metal.

--> place the wire loop in the side of the flame and observe the colour of the flame.

Result of flame tests of some metallic ion will show the following:

--> sodium ion will give yellow colour flame

--> potassium ion will give lilac colour flame

--> calcium ion will give orange-red colour flame