According to Molecular Orbital Theory, which of the following statements is(are) correct?

The correct order of acidity for the following compounds is

The major product of the following reaction sequence is:

In the following reaction, sequence in aqueous solution, the species X, Y and Z, respectively, are

$${S_2}O_3^{2 - }\buildrel {A{g^ + }} \over \longrightarrow \mathop X\limits_{Clear\,solution} \buildrel {A{g^ + }} \over \longrightarrow \mathop Y\limits_{White\,precipitate} \buildrel {With\,time} \over \longrightarrow \mathop Z\limits_{Black\,precipitate} $$