The value of x in `[Cr(H_(2)O)_(6)]^(x)` when Cr is in +3 oxidation state is

The oxidation state of Cr in Cr_(2)O_(7)^(2-) is

The oxidation state of Cr in Cr_(2)O_(7)^(2-) is

The oxidation state of Cr in Cr(CO)_(6) is

The oxidation state of Cr in [Cr(NH_(3))_(4)Cl_(2)]^(+) is

When SO_(2) is passed through acidified K_(2)Cr_(2)O_(7) solution, Cr_(2)(SO_(4))_(3) is formed. The change in oxidation state of Cr is -