Question

Given below are two statements: one is labelled as Assertion A and the other is labelled as Reason R
Assertion A: The FTIR spectrum of a compound is generally used to identify the functional groups present in it.
Reason R: As each functional groups have different elements and chemical-bonds as compared to main elements present in it.
In the light of the above statements, choose the most appropriate answer from the options given below:

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

Hint:

Think of an FTIR spectrum as a "molecular fingerprint." Just as no two people have the same fingerprint, no two different functional groups vibrate at exactly the same frequency.

Answer 1

The Correct Option is A

Concept: Fourier Transform Infrared (FTIR) spectroscopy measures the absorption of infrared radiation by a sample. This absorption corresponds to the vibrational frequencies of chemical bonds within the molecule.

Step 1: Analyze Assertion A.
FTIR is a primary tool for functional group identification. Because different bonds (like C=O, O-H, or C-N) vibrate at specific frequencies, their presence results in characteristic "peaks" in the IR spectrum. Thus, Assertion A is correct.

Step 2: Analyze Reason R.
The reason different groups have unique vibrational frequencies is due to the specific masses of the atoms involved and the strength of the chemical bonds between them. Each functional group represents a unique chemical environment that differs from the rest of the molecule. This uniqueness is what allows FTIR to distinguish between them. Thus, Reason R is correct and explains A.