Question

Which of the following salt gives a crimson red colour in the flame test?
(A) $BaCl_{ 2 }$
(B) $CaCl_{ 2 }$
(C) $BeCl_{ 2 }$
(D) $SrCl_{ 2 }$

Answer 1

Hint: The salt which will give a crimson red colour in the flame test is a chloride from the fifth period of the periodic table. Now try to find the correct answer using this hint.

Complete step by step answer:
We should know that a flame test is an analytical procedure used in chemistry to detect the presence of certain elements, primarily metal ions, based on each element's characteristic emission spectrum. When the atoms of a gas or vapour are excited, for instance by heating or by applying an electrical field, their electrons are able to move from their ground state to higher energy levels.
The colour of flames in general also depends on the temperature

In the flame test, strontium chloride ($SrCl_{ 2 }$) will give crimson red colour. The reason behind this excitation of an electron from ground level to the higher energy level by heating and de-excitation of electrons to the ground state with the emission of light in the visible region.

Therefore, we can conclude that the correct answer to this question is option D.

Note: Let’s us discuss other options too -
Light Green Flame shows presence Of Barium Chloride ($BaCl_{ 2 }$)
Orange Flame shows presence Of Calcium Chloride ($CaCl_{ 2 }$)

Beryllium and magnesium do not give any colour to the flame test because they have a small size and very high ionization enthalpies. The energy of the flame is not sufficient to excite the electrons to higher energy levels. Hence, they do not impart any characteristic colour to the flame.