Question

Identify a reagent from the following list which can easily distinguish between 1-butyne and 2-butyne.

• A. $B{r}_2$, $CC{l}_4$
• B. $H_2,Pd,BaS{O}_4$
• C. Dilute $H_{2}S{O}_4$, $HgS{O}_4$
• D. $\left[Ag\right(N{H}_3{)}_2]N{O}_3$

Answer 1

The correct option is D $\left[Ag\right(N{H}_3{)}_2]N{O}_3$

Only terminal alkynes (but-1-yne) react with ammoniacal solution of silver nitrate $\left(AgN{O}_3\right)$ or cuprous chloride (CuCl).
$C{H}_3-C{H}_2-C\equiv CH+2\left[Ag\right(N{H}_3{)}_2]N{O}_3\to C{H}_3-C{H}_2-C\equiv C^{-}A{g}^{+}\text{white ppt}$

$C{H}_3-C\equiv C-C{H}_3+2\left[Ag\right(N{H}_3{)}_2]N{O}_3\to \text{No reaction}$
Hence correct option is d.