To determine the correct order of acidity, we need to consider the acidity of hydrocarbons.$\\$The acidity of hydrocarbons is influenced by the hybridization of the carbon atom attached to the hydrogen.$\\$The general order of acidity based on hybridization is:$\\$• sp hybridized (alkynes) $>$ sp$^2$ hybridized (alkenes) $>$ sp$^3$ hybridized (alkanes).$\\$Let's analyze each compound in the options:$\\$1. $CH \equiv CH$ (acetylene)$\\$• The carbon is sp hybridized, making it the most acidic.$\\$2. $CH_3 - C \equiv CH$ (propyne)$\\$• The terminal alkyne has an sp hybridized carbon, making it less acidic than acetylene but more acidic than alkenes and alkanes.$\\$3. $CH_2 = CH_2$ (ethylene)$\\$• The carbon is sp$^2$ hybridized, making it less acidic than alkynes.$\\$4. $CH_3 - CH_3$ (ethane)$\\$• The carbon is sp$^3$ hybridized, making it the least acidic.$\\$Based on the above analysis, the correct order of acidity is:$\\ CH \equiv CH > CH_3 - C \equiv CH > CH_2 = CH_2 > CH_3 - CH_3 \\$Therefore, the correct option is Option 1.