Question

How will you convert acetylene into but-1yne?

Answer 1

Hint: This reaction will occur in multiple steps. One might require to add a base or an acid to lead towards the product. A basic alkyl halide is used to form the final product, which is a step in between the initial and the last one.

Complete answer:
The acetylene formula is: \[H - C \equiv C - H\]
The formula for but-1-yne:\[{H_2}C = CH - C{H_2} - C{H_3}\]
The H of acetylene is acidic, because when \[{H^ + }\] proton loss, we get an anion.
In step one: the \[{H^ + }\] proton loss, anion we get is \[HC \equiv {C^ - }\]
\[H - C \equiv C - H \to HC \equiv {C^ - }\]
We are aware of triple bond; the s character is 50%. This means it is more electronegative, and it will attract the less electron rich atoms to stabilise the atom.

In step two: Now if we react the anion with \[NaN{H_2}\] a base, the protonic \[{H^ + }\] will loose and the rest highly negative anion will react\[N{a^ + }\] and form with amino group forms ammonia.
\[HC \equiv {C^ - }\xrightarrow{{NaN{H_2}}}HC \equiv {C^ - }N{a^ + } + N{H_3}\]
In step third: we react the above formed with \[{C_2}{H_5}Br\] we get,
\[
  {C_2}{H_5}Br + HC \equiv {C^ - }N{a^ + } \to NaBr + CH \equiv CHC{H_2}C{H_3}_{} \\
    \\
\ \].
Acetylene is also called ethyne, which is the simplest and best known member of the hydrocarbon series containing one or more pairs of carbon atoms linked with a triple bond. But-1-yne is a terminal acetylenic compound that is butane carrying a triple bond at first carbon.

Note:
It is an inflammable, colourless gas used quite often as fuel for welding. It is even used for cutting of metals and as a raw material for synthesis of plastics. It is highly unstable and can result in explosion or fire.It has unique transportation requirements.