In which of the following arrangements, given sequence is not according to the property indicates against it-

Options

A. `H_(2)O lt H_(2)S lt H_(2)Se lt H_(2)Te`: increasing `pK_(a)` values
B. `NH_(3) lt PH_(3) lt AsH_(3) lt SbH_(3)`: increasing acidity
C. `CO_(2) lt SiO_(2) lt SnO_(2) lt PbO_(2)`: increasing oxidising power
D. `HF lt HCl lt HBr lt HI`: increasing acidic strength

Answer

A

Explanation

On moving down a grou in the periodic table, covalent character of the hydrides of the elements increases and so their acidity gradually increases. Therefore, acidic character of the hydrides of the elements of group VA and VIIA follows the order-
`NH_(3) lt PH_(3) lt AsH_(3) lt SbH_(3) and HF lt HCl lt HB r lt HI` on the other hand, the oxidising power of the oxides in option (c) follows the trend:
`CO_(2) lt SiO_(2) lt SnO_(2) lt PbO_(2)`.