Tertiary amino group is found in:

The correct answer is Option (3) → Benadryl

Note 1: The given answer is as per the official NTA Answer Key. However, there is more than one correct option for this question, as explained below.

An amine is tertiary when the nitrogen carries no hydrogen and is bonded to three carbon groups (R₃N); a secondary amine has one N–H (R₂NH).

• Option (1) Novocain — Is also correct. Novocain (procaine), H₂N–C₆H₄–CO–O–CH₂CH₂–N(C₂H₅)₂, has a tertiary –N(C₂H₅)₂ group in its side chain, besides a primary aromatic –NH₂.

• Option (2) Ephedrine — Incorrect. It contains a secondary amino group (–NH–CH₃).

• Option (3) Benadryl — Is also correct. Benadryl (diphenhydramine), \( \ce{(C6H5)2CH-O-CH2CH2-N(CH3)2} \), an antihistaminic drug, has a nitrogen bonded to three carbon groups and no hydrogen: a tertiary amino group.

• Option (4) Adrenaline — Incorrect. It also contains a secondary amino group (–NH–CH₃).

NCERT (2026-27 edition):
Amines – “… Two biologically active compounds, namely adrenaline and ephedrine, both containing secondary amino group, are used to increase blood pressure. Novocain, a synthetic amino compound, is used as an anaesthetic in dentistry. Benadryl, a well known antihistaminic drug also contains tertiary amino group. Quaternary ammonium salts are used as surfactants.”

Note 2: The same/similar question has been asked in different years by NTA as per the details given below: