Question

Which of the following is the most suitable reagent used to distinguish compound (3) from rest of the compounds? 1. ${\mathrm{CH}}_3-\mathrm{C}\equiv \mathrm{C}-{\mathrm{CH}}_3$2. ${\mathrm{CH}}_3-{\mathrm{CH}}_2-{\mathrm{CH}}_2-{\mathrm{CH}}_3$3. ${\mathrm{CH}}_3-{\mathrm{CH}}_2\mathrm{C}$ : $\mathrm{CH}$4. ${\mathrm{CH}}_3-\mathrm{CH}={\mathrm{CH}}_2$

• (A) Bromine in carbon tetrachloride
• (B) Bromine in acetic acid
• (C) Alkaline KMnO4
• (D) Ammoniacal silver nitrate

Answer 1

The Correct Option is D

Explanation:
Ammoniacal silver nitrate is used to distinguish terminal alkynes groups.But-1-yne reacts with ammoniacal silver nitrate to give a white precipitate. ${\mathrm{CH}}_3^{-}{\mathrm{CH}}_2-\mathrm{C}\equiv \mathrm{CH}\frac{\mathrm{A}{\left({\mathrm{NH}}_3\right)}_2(\mathrm{va})}{(\mathrm{in}\mathrm{amm}\text{ oniacal cilver nitrate })}={\mathrm{CH}}_3{\mathrm{CH}}_2\mathrm{C}\equiv {\mathrm{C}}^{-}{\mathrm{Ag}}^{+}(\mathrm{s})$but-1-yne$${\mathrm{CH}}_3-\mathrm{C}\equiv \mathrm{C}-{\mathrm{CH}}_3⟶\mathrm{no}\text{ reaction }$$ but-2-yne