Question

Which compound on the left, when dissolved

in water, does not produce the corresponding
compound(s) on the right?
1. CaO ! Ca(OH)2
2. SO2 ! H2SO4
3. NaH ! NaOH + H2
4. N2O5 ! HNO3
5. Cl2O7 ! HClO4

Answer 1

#2 is the incorrect one. SO2 is the anhydride of H2SO3; SO3 is the anhydride of H2SO4.