The empirical formula of a ompound is c2h5 and its formula mass is 58 amu. what is the molecular formula

The empirical formula of the compound is C₂H₅. Empirical formula is the simplest  ratio of whole numbers of components in a compound.
the mass of one empirical unit = (12 x 2) + (1 x 5)= 29
the molecular mass of the compound - 58 a.m.u
the number of empirical units = molecular mass/mass of empirical unit
                                               = 58 / 29 = 2
There are 2 empirical units
Molecular formula - 2(C₂H₅)
therefore molecular formula - C₄H₁₀