In which of the following arrangements, the sequence is not strictly according to the property written against it?
(1) CO2 < SiO2 < SnO2 < PbO2 : increasing oxidising power
(2) B < C < O < N : increasing first ionisation enthalpy
(3) NH3 < PH3 < AsH3 < SbH3 : increasing basic strength
(4) HF < HCl < HBr < HI : increasing acid strength