Name: Oxidising Nature of Potassium Permanganate
Uploaded: 2019-07-19
Duration: 7 min 2 s
Description: Potassium permanganate is a very strong oxidising agent, widely used in the chemical industry and laboratories. Let us learn more through this video.

Question

What is the oxidation state of chromium in chromate ion and dichromate ion?

Accepted Answer

Chromate ion or chromate anion is present in chromate salts. When chromate salt dissociates, we get chromate ions. It consists of one chromium and four oxygen atoms. The formula of chromate ion is ${CrO}_{4}^{2 -}$ .

The charge on the chromate ion is $- 2$ .

The oxidation state of oxygen is $- 2$ .

$x + 4 \times (- 2) = - 2 x - 8 = - 2 x = - 2 + 8 x = + 6$

So, the oxidation state of $Cr$ in chromate ion is $+ 6$ .

Dichromate ions are obtained from dissociation of dichromate salts. As the name suggests, there are two chromium atoms in dichromate ion. Dichromate is also an anion. It has an ionic charge of $- 2$ .

The formula of dichromate ion is ${Cr}_{2} {O_{7}}^{2 -}$ .

Total oxidation state of dichromate ion is $- 2$ .

Oxidation state of oxygen in dichromate ion is $- 2$ .

So, $2 \times x + 7 \times (- 2) = - 2$

$2 x - 14 = - 2 2 x = - 2 + 14 x = + \frac{12}{2} x = + 6$

So, the oxidation state of $Cr$ in dichromate ion is $+ 6$ .

What is the oxidation state of chromium in chromate ion and dichromate ion?

Important Questions on The d- and f-Block Elements

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