Question

The deep pink colour is given to flame by the salts of
A. Strontium
B. Potassium
C. Zinc
D. Barium

Answer 1

Hint: A salt when heated is provided with an amount of energy.
This energy is absorbed by the matter due to which flame is observed with a colour.
This phenomenon can be used as a criterion to learn about the identity of the element or compounds formed by it.

Complete Step by Step Solution:
When a certain amount of energy is provided to any compound, the energy of the constituent atoms present in the substance increases as the compound absorbs this energy.
If metal is heated then the electrons present in the consistent atoms absorb this energy, become excited and are raised to higher energy levels from their ground state.

When these electrons return to their ground state, they emit energy. This emitted energy is in the form of visible light with characteristic colours. So, the flame of an element has a certain colour. This phenomenon is shown mainly by alkali metals and alkali earth metals.

These metals have low ionisation energy because of the presence of less number of valence electrons, it is easy to remove an electron from the outer shell. So, the valence electrons absorb the energy provided to them easily. Out of the given options, the flame of salts of Sr shows deep pink colouration.
So, option A is correct.

Additional Information: Beryllium and magnesium atoms are smaller so the electrons in these atoms are tightly held. Hence, they are not excited by the energy of the flame.

Note: The electronic configuration of the metals may be shown by the salts formed by them with different anions. So, the salts of alkali metal and alkali earth metals show similar colours for the flame frequently.