Question

Acidification of chromate gives 'Z'. The oxidation state of chromium in 'Z' is

• A. +3
• B. +6
• C. +7
• D. +2

Hint:

Remember that acidification of chromate leads to dichromate formation, and the oxidation state of chromium remains the same in both chromate and dichromate.

Answer 1

The Correct Option is B

Acidification of chromate (CrO$_4^{2-}$) leads to the formation of dichromate (Cr$_2$O$_7^{2-}$). 
The reaction is: 
2CrO$_4^{2-}$ + 2H$^+$ → Cr$_2$O$_7^{2-}$ + H$_2$O The 'Z' in this reaction is dichromate (Cr$_2$O$_7^{2-}$). 
To find the oxidation state of chromium in Cr$_2$O$_7^{2-}$, let the oxidation state of Cr be x.
2x + 7(-2) = -2 
2x - 14 = -2 
2x = 12 
x = +6 
Therefore, the oxidation state of chromium in dichromate is +6.