Certain inorganic salt, when introduced in flame, produces crimson red colour. It indicates the presence of:
A.Strontium ion
B.calcium ion
C.barium ion
D.none of the above

Hint: It is an alkaline earth metal. It belongs to the second group of the periodic table. Its electronic configuration is \[[Kr]5{{s}^{2}}\]. This means that the principal quantum number (n) of the metal is 5, hence lying in the fifth period of the periodic table. Sir Humphry Davy discovered the element. It is used in the fireworks for its bright colour emission property.

Complete step by step answer:
1.Certain inorganic salt, when introduced in flame, produces crimson red colour. It indicates the presence of the strontium ion.
2.Flame tests emit colours because of the excitation of the atoms of the element by applying an external electric field from the ground state to the excited state.
3.When they return to the ground state energy levels, they emit photons of specific energy which correspond to the various wavelengths of light, giving particular lights.
4.Strontium ion gives crimson red colour on the flame test.
5.It is also used to make ferric magnets, refining zinc paints.
6.One of its isotopes, Sr-90 is radioactive in nature. It is used to produce electricity in space vehicles.
7.It is of no use to the human body and non-toxic.
So, the correct option is A.

Note: Don't confuse between the colour given in the flame by strontium and calcium. Strontium gives crimson red colour while calcium gives brick red colour.