The gaseous mixture used for welding of metals is

How many structures are possible for $C_5H_8$ with one triple bond?

Provide the chemical reactions for the following conversions:
$(1)$ Propyne from ethyne
$(2)$ $2-$butyne and $1-$butyne from ethyne

Which of the following compounds do not react with $NaNH_2$? Why?
$CH_3-C \equiv C-CH_3, CH_3-CH_2-C \equiv CH, C_2H_5-C \equiv C-C_2H_5, HC \equiv CH, CH_3-CH=CH_2, CH_2=CH-C \equiv CH$

$A$ hydrocarbon $X$ with molecular formula $C_4H_6$ decolourises bromine water and forms a white precipitate in ethanolic $AgNO_3$ solution. Treatment of $X$ with $HgCl_2$ in aqueous $H_2SO_4$ produces a compound,which gives a yellow precipitate when treated with $I_2$ and $NaOH$. The structure of $X$ is

Discuss the types of reactions given by alkynes.