The compound (NH4)2SO4 is most accurately classified as which type of pure substance?
a) A molecular compound because all the atoms present are nonmetals
b) An ionic compound composed of ammonium cations and sulfate anions
c) A network-covalent solid consisting of an extended lattice of covalently bonded atoms
d) An acid salt that will yield H2SO4 when dissolved, so it is best described as an acidic compound rather than an ionic solid