Question

which isn't a pure substance?

1.Cl2(g)
2.Fe(s)
3.O2(aq)
4.C6H12O6(b)
5.H2O(l)

Answer 1

I assume g stands for gas, s for solid, aq for aqueous and l for liquid. But I don't know what b would stand for in #4. Solid, liquid, gas, aqueous are about the only combinations I know of except for plasma etc.