Select the incorrect statements:

Options

A. In `K_2MnO_4` and `CrO_2Cl_2` , the central transition mtals ion have the same oxidation state
B. Both sodium and potassium dichromate can be used as primary standard in volumetric estimations
C. Potassium dichromate on strong heating evolves oxygen gas and forms green powder
D. Potassium permanganate on fusion with potassium hydroxide liberates oxygen gas leaving behind green residue

Answer

B

Explanation

(A)In both compounds central metal has +6 oxidation state
(B)Sodium dichromate is `Na_2Cr_2O_7. 2H_2O`, so it can not be weighed correctly for the prepartion of standard solution.
(C )`2K_2Cr_2O_7 oversetDeltato2K_2CrO_4 +Cr_2O_3`(green ) +`3//2 O_2 uarr`
(D)`4KMnO_4 + 4KOH oversetDeltato 4K_2 MnO_4` (green residue) +`2H_2O uarr + O_2 uarr`