Describe the physical properties of alkynes.

(N/A) The physical properties of alkynes follow trends similar to those of alkanes and alkenes.
$1$. Physical State: The first three members $(C_2H_2, C_3H_4, C_4H_6)$ are gases. The next eight members ($C_5H_8$ to $C_{12}H_{22}$) are liquids,and higher members are solids.
$2$. Colour and Odour: All alkynes are colourless. Ethyne has a characteristic odour,while other members are generally odourless.
$3$. Solubility: Alkynes are weakly polar. They are lighter than water and immiscible with water,but they are soluble in organic solvents like ether,carbon tetrachloride $(CCl_4)$,and benzene $(C_6H_6)$.
$4$. Boiling and Melting Points: Boiling points,melting points,and densities increase with an increase in molar mass. For similar molecular weights,the boiling point order is: $CH_3-CH_3 < CH_2=CH_2 < CH \equiv CH$.