Propene and propyne can be distinguished by

What is the product formed when two molecules of $HBr$ are added to $CH_3 - C \equiv CH$?

In the reaction,$H_3C-C\equiv C-H$ $\xrightarrow[2. x]{1. NaNH_2, \Delta}$ $\xrightarrow{3. y} H_3C-CH=CH-CH_3$ (trans form),$x$ and $y$,respectively are

Schemes $1$ and $2$ describe the sequential transformation of alkynes $M$ and $N$. Consider only the major products formed in each step for both the schemes.
$1.$ The product $X$ is:
$2.$ The correct statement with respect to product $Y$ is:
$(A)$ It gives a positive Tollens test and is a functional isomer of $X$.
$(B)$ It gives a positive Tollens test and is a geometrical isomer of $X$.
$(C)$ It gives a positive iodoform test and is a functional isomer of $X$.
$(D)$ It gives a positive iodoform test and is a geometrical isomer of $X$.

Which of the following has the shortest $C - C$ bond length?

What is the final product,$C$ of the following reaction sequence?
$CH_3CH_2-C \equiv CH$ $\xrightarrow[2. CH_3CH_2Br]{1. NaNH_2} A$ $\xrightarrow{Na, NH_3(liq.)} B$ $\xrightarrow{Br_2, CH_2Cl_2} C$