Question

Assertion :Emission of light as a result of exposure of P to air in night is called phosphorescence. Reason: Phosphrous burns in $O_2$ to give $P_2{O}_5$ and conversion of chemical energy into light energy producing cold light and the phenomenon is called chemi-luminescence.

• A. Both Assertion and Reason are correct and Reason is the correct explanation for Assertion
• B. Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion
• C. Assertion is correct but Reason is incorrect
• D. Assertion is incorrect but Reason is correct

Answer 1

The correct option is D Assertion is incorrect but Reason is correct

Option (D) is correct.
$A$ : Emission of light as a result of exposure of P to air in night is called chemi-luminescene. It is the term for light thats emitted as a product of chemical reactions. Chemiluminescent reactions produce unstable products, which then decay in order to form more stable products. In the process, energy is emitted in the form of light.
Phosphorus vapor absorbed into the air around the solid is oxidized, producing $HPO$ and $(PO{)}_2$ in their excited states. Green light is emitted as the molecules return to their stable, lower energy states.