Question:

The correct sequence of decreasing number of pi-bonds in the structures of H2SO3, H2SO4, and H2S2O7 is:

H2S2O7>H2SO4>H2SO3

H2SO4>H2S2O7>H2SO3

H2S2O7>H2SO3>H2SO4

H2SO3>H2SO4>H2S2O7

The correct sequence of decreasing number of pi-bonds is H2S2O7(4) > H2SO4(2) > H2SO3(1). The numbers in bracket indicate the number of pi bonds.