Question

Given below are two statements, one is labelled as Assertion $A$ and the other is labeled as Reason $R$ 
Assertion A : The alkali metals and their salts impart characteristic colour to reducing flame 
Reason R : Alkali metals can be detected using flame tests 
In the light of the above statements, choose the most appropriate answer from the options given below

• A. $A$ is not correct but $R$ is correct
• B. Both $A$ and $R$ are correct but $R$ is NOT the correct explanation of $A$
• C. Both $A$ and $R$ are correct and $R$ is the correct explanation of $A$
• D. $A$ is correct but $R$ is not correct

Answer 1

The Correct Option is A

Assertion A is incorrect. Alkali metals and their salts typically impart distinct colors to an oxidizing flame, not a reducing flame. When alkali metal salts are heated in a flame, they excite the metal ions, which then emit characteristic colors as they return to their ground state. These colors are observed in an oxidizing flame (such as that produced by a Bunsen burner with sufficient oxygen), not in a reducing flame, which lacks the necessary oxidizing conditions for such reactions to occur. 

Reason R is correct. Flame tests are indeed a common and reliable method for identifying alkali metals and other metal ions based on the characteristic colors they emit when heated. For example, lithium produces a red flame, sodium a bright yellow flame, and potassium a lilac flame. This principle is widely used in qualitative analysis.