52 g/mol
The molar mass of a compoiund is the ratio of the mass of the compund to the amount of substance in the sample.
The molar mass of C4H4 is expressed as shown below;
[tex]\begin{gathered} molar\text{ mass of }C_4H_4=4(12)+4(1) \\ molar\text{ mass of }C_4H_4=48+4 \\ molar\text{ mass of }C_4H_4=52gmol^{-1} \end{gathered}[/tex]Hence the molar mass of C4H4 is 52 g/mol