In which one of the following arrangements the given sequence is not strictly according to the properties indicted against it?
CO2 < SiO2 < SnO2 < PbO2 : Increasing oxidizing order
HF < HCl < HBr < HI : Increasing acidic strength
H2O < H2S < H2Se < H2Te : Increasing pKa values
NH3 < PH3 < AsH3 < SbH3 : Increasing acidic character
