Question

Given below are two statements: One is labelled as Assertion A and the other is labelled as Reason R:
Assertion (A): B_eCl₂ and MgCl₂ produce characteristic flame. 
Reason (R) : The excitation energy is high in B_eCl₂ and MgCl₂ 
In the light of the above statements, choose the correct answer from the option given below

• A. Both (A) and (R) are true but (R) is NOT the correct explanation of (A)
• B. (A) is false but (R) is true
• C. Both (A) and (R) are true and (R) is the correct explanation of (A)
• D. (A) is true but (R) is false.

Hint:

Flame tests are effective for metals with low ionization energies, like alkali metals

Answer 1

The Correct Option is D

Analysis of Beryllium and Magnesium Flame Test

Key Observations:

• Beryllium (Be) and Magnesium (Mg) have exceptionally high ionization energies due to their small atomic size and strong nuclear attraction.
• High ionization energies prevent sufficient excitation of electrons to higher energy levels when exposed to a flame.
• As a result, neither element produces a characteristic flame color during flame tests.

Assertion (A) and Reason (R):

• Assertion (A): Beryllium and magnesium produce a flame color due to their excitation energy. This is false because no characteristic color is observed for these elements.
• Reason (R): The high ionization energy of Be and Mg prevents electron excitation to higher energy levels. This is correct.

Conclusion:

The assertion (A) is false, but the reason (R) correctly explains why Be and Mg do not exhibit a characteristic flame color.