JEE Main · 2021 · 26 Feb 2021 · Shift 1 · d and f Block Elements

Dichromate ion is treated with base, the oxidation number of Cr in the product formed is ______

Answer: 6

Solution

Alkali converts the dichromate ion into the chromate ion:

C r_{2} O_{7}^{2 -} + 2 O H^{-} \to 2 Cr O_{4}^{2 -} + H_{2} O

No electron transfer takes place in this change; the dichromate ion is merely broken into two chromate ions by the alkali. For the chromate ion each oxygen counts as

- 2

, so

x + 4 (- 2) = - 2 \Rightarrow x = + 6

The oxidation number of chromium in the product is

6

JEE Main · 2021 · 26 Feb 2021 · Shift 1 · Integer answer

Practise more: all JEE Main PYQs on d and f Block Elements →

More JEE Main questions on d and f Block Elements

$MnO_{4}^{2 -}$ , in acidic medium, disproportionates to :
JEE Main 2026View solution →
Consider the following reactions:
$NaCl + K_{2} Cr_{2} O_{7} + H_{2} SO_{4} \to A + KHSO_{4} + NaHSO_{4} + H_{2} O$ …
JEE Main 2026View solution →
Given below are some of the statements about Mn and $Mn_{2} O_{7}$ . Identify the correct statements
A. Mn forms the oxide $Mn_{2} O_{7}$ in which Mn is in its highest oxidation state.
B. Oxygen stabilizes the Mn in higher oxidation states by fo …
JEE Main 2026View solution →
On heating a mixture of common salt and $K_{2} Cr_{2} O_{7}$ in equal amount along with concentrated $H_{2} SO_{4}$ in a test tube, a gas is evolved. Formula of the gas evolved and oxidation state of the central metal atom in the gas r …
JEE Main 2026View solution →
Among the following oxides of 3d elements, the number of mixed oxides are _____. …
JEE Main 2026View solution →
The oxidation state of chromium in the final product formed in the reaction between KI and acidified $K_{2} Cr_{2} O_{7}$ solution is:
JEE Main 2026View solution →