F# on guitar for chemicals react?

If the chord is F# (or G#m) you can't use a different chord - it'll sound wrong! I'm surprised you can play B, but not F# or G#m. Why don't you transpose the song down to D and use a capo at the 2nd fret? E would be D, B would be C, F# would be E and G#m would be..... F#m (just an idea!).