Question

The functional group of a secondary amine is

• A. \(-\mathrm{NH}-\)
• B. \(-\mathrm{NH_2}\)
• C. \(\mathrm{NH_3}\)
• D. \(\mathrm{NH_3^+}\)

Hint:

Primary: \(\mathrm{R{-}NH_2}\); Secondary: \(\mathrm{R{-}NH{-}R'}\); Tertiary: \(\mathrm{R_3N}\).

Answer 1

The Correct Option is A

Step 1: Definition.
A secondary amine has the general formula \(\mathrm{R{-}NH{-}R'}\) with two alkyl/aryl groups attached to nitrogen and one hydrogen.
Step 2: Analyze options.
(A) \(-\mathrm{NH}-\): Correct representation of secondary amine linkage.
(B) \(-\mathrm{NH_2}\): Primary amine group.
(C) \(\mathrm{NH_3}\): Ammonia, not an amine functional group in an organic chain.
(D) \(\mathrm{NH_3^+}\): Protonated ammonium, not the neutral secondary amine group.
Step 3: Conclusion.
Hence, the functional group for a secondary amine is \(-\mathrm{NH}-\).