When H2SO3 is converted into H2SO4 the change in the oxidation state of sulphur is from:
0 to +2
+2 to +4
+4 to +2
+4 to +6
When K2Cr2O7 is converted to K2CrO4 the change in the oxidation state of chromium is
The oxidation number of sulphur in sulphur dioxideSO2 and sulphuric acidH2SO4 is respectively
The oxidation state of Cr in CrO5 is