Acompound contains 81.1 boron with the remainder being hydrogen what is the empirical formula of the compound

Empirical formula is the simplest ratio of whole numbers of components making up the compound
Mass percentage of boron - 81.1 %
Mass percentage of hydrogen - 18.9 %
For 100 g of the compound
                                               B                        H
Mass                                   81.1 g                  18.9 g
Number of moles          81.1 g /11 g/mol       18.9 g/1 g/mol
                                          = 7.37 mol             = 18.9 mol
Divide by the least number of moles
                                           7.37/7.37 =1.00     18.9/7.37 =2.56
Since we get 2.56 that cannot be rounded off we have to multiply both boron and hydrogen values by 2
B = 1.00 x2 = 2.00
H = 2.56 x 2 = 5.12 rounded off to 5
Therefore empirical formula is
B₂H₅

Most smaller stars don't have a radiative zone.