Propyne$\underset{∆}{\overset{\mathrm{Na}}{\to }} \mathrm{X} +\frac{1}{2}{\mathrm{H}}_2$ 

                 $\mathrm{X} \underset{∆}{\overset{{\mathrm{CH}}_3\mathrm{I}}{\to }}\mathrm{Y}$  Now, which of the following reagents can be used to distinguish Y from propyne?

 

 

 

Propyne is a terminal alkyne and exhibits acidic character,hence they gives +ve test with ${\mathrm{NH}}_4\mathrm{OH}+{\mathrm{AgNO}}_3 \mathrm{and} {\mathrm{NH}}_4\mathrm{OH}+{\mathrm{Cu}}_2{\mathrm{Cl}}_2$

Where as Y[but-2-yne] is a internal alkyne,it does not contain acidic hydrogen,hence it does not give +ve test with the above two reagents.