Q. Which pair of the following chlorides do not impart colour to the flame?
A) $BeCl_{2}\ and\ SrCl_{2}$
B) $BeCl_{2}\ and\ \ MgCl_{2}$
C) $CaCl_{2}\ and\ BaCl_{2}$
D) $BaCl_{2}\ and\ \ \ SrCl_{2}$
Explanation
(b)
Among the alkaline earth metals, the size of beryllium and magnesium metals is very small. Therefore, the electrons in these metals are bounded more strongly and are not excited by the energy of flame to higher energy states. Hence, these metals or their salts do not impart any colour to the flame.
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.