More practice questions

3. Q3. How many hydrogen atoms are left on nitrogen in a primary, a secondary and a tertiary amine, and in a quaternary ammonium ion?

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   Two, one and none; a quaternary ammonium ion, R₄N⁺, has none either, and no unshared pair (reasoned from NCERT pages 260 and 262).

4. Q4. Propan-2-ol is a secondary alcohol. Is propan-2-amine, (CH₃)₂CHNH₂, a secondary amine? (Compare NCERT Exercise 9.1 (i), page 278.)

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   No, it is primary: its nitrogen carries only one carbon group, the isopropyl group. Alcohol classes describe the carbon carrying –OH; amine classes count the groups on nitrogen (reasoned from NCERT page 260).

5. Q5. Which of (CH₃)₂NH, CH₃NHC₂H₅ and (C₆H₅)₃N are simple amines?

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   (CH₃)₂NH and (C₆H₅)₃N, whose groups on nitrogen are all alike; CH₃NHC₂H₅ is mixed (reasoned from NCERT page 260).

6. Q6. Classify each nitrogen of ethane-1,2-diamine, H₂N–CH₂–CH₂–NH₂.

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   Both are primary: each –NH₂ carries one carbon group and two hydrogens (reasoned from NCERT page 260).