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