CrO₄^2- (yellow) changes to Cr₂O₇^2- (orange) in pH = x and vice versa in pH = y.

The value of x and y will be:

1. 6, and 8

2. 6, and 5

3. 8, and 6

4. 7, and 7

The colour of KMnO₄ is due to  :

1. d-d transition

2. Charge transfer spectra

3. Polarisation of ion

4. p-d transition

Cr₂O₇^2-+X$\stackrel{{\mathrm{H}}^{+}}{\to }$Cr³⁺+H₂O + oxidized product of X. X in the above reaction cannot be

1. C₂O₄^2-

2. Fe²⁺

3. SO₄^2-

4. S^2-

In the dichromate ion Cr₂O₇^2-,

1. 4 Cr-O bonds are equivalent

2. 6 Cr-O bonds are equivalent

3. All Cr-O bonds are equivalent

4. None of Cr-O bonds are equivalent

Name the gas that can readily decolourise acidified KMnO₄ solution.

(1) CO₂           

(2) SO₂           

(3) NO₂             

(4) P₂O₅