6. ⇒ (JEE Main 2021 (Online) 27th July Morning Shift)

The oxidation states of 'P' in H₄P₂O₇, H₄P₂O₅ and H₄P₂O₆, respectively, are

A. 7, 5 and 6

B. 5, 4 and 3

C. 5, 3 and 4

D. 6, 4 and 5

Correct option is (C)

Oxidation state of P in H₄P₂O₇, H₄P₂O₅ and H₄P₂O₆ is 5, 3 & 4 respectively

H₄P₂O₇

2x + 4(+ 1) + 7 ( $-$ 2) = 0

x = + 5

$H_{4} \underset{―}{P_{2}} O_{5}$

2x + 4(+ 1) + 5 ( $-$ 2) = 0

x = + 3

$H_{4} \underset{―}{P_{2}} O_{6}$

2x + 4 (+ 1) + 6( $-$ 2) = 0

x = +4

7. ⇒ ( JEE Main 2021 (Online) 25th July Evening Shift)

Identify the process in which change in the oxidation state is five :

A. $C r_{2} O_{7}^{2 -} \to 2 C r^{3 +}$

B. $M n O_{4}^{-} \to M n^{2 +}$

C. $C r O_{4}^{2 -} \to C r^{3 +}$

D. $C_{2} O_{4}^{2 -} \to 2 C O_{2}$

Correct option is (B)

$M n O_{4}^{-} + 5 e \to M n^{+ 2}$

8. ⇒ (JEE Main 2020 (Online) 2nd September Evening Slot)

The oxidation states of transition metal atoms in K₂Cr₂O₇, KMnO₄ and K₂FeO₄, respectively, are x, y and z. The sum of x, y and z is _______.

Correct option is 19

K₂Cr₂O₇

Let oxidation state of Ce

2(+1) + 2x + 7(–2) = 0

$\Rightarrow$ x = +6

In K₂Cr₂O₇, Transition metal (Cr) present in +6 oxidation state.

KMnO₄

(+1) + y + 4(–2) = 0
$\Rightarrow$ x = +7

In KMnO₄, transition metal (Mn) present in +7 oxidation state.

K₂FeO₄

2(+1) + z + 4(–2) = 0
$\Rightarrow$ x = +6

In K₂FeO₄, transition metal (Fe) present in +6 oxidation state.

$∴$ x + y + z = 6 + 7 + 6 = 19

9. ⇒ (JEE Main 2020 (Online) 7th January Morning Slot)

Oxidation number of potassium in K₂O. K₂O₂ and KO₂ respectively is :

A. +1, +2 and + 4

B. +1, +1 and + 1

C. +2, +1 and $+ \frac{1}{2}$

D. +1, +4, and +2

Correct option is (B)

Potasisum has an oxidation of +1 (only) in combined state.

10. ⇒ (JEE Main 2019 (Online) 9th April Morning Slot)

The correct order of the oxidation states of nitrogen in NO, N₂O, NO₂ and N₂O₃ is :

A. NO₂ < NO < N₂O₃ < N₂O

B. NO₂ < N₂O₃ < NO < N₂O

C. N₂O < NO < N₂O₃ < NO₂

D. N₂O < N₂O₃ < NO < NO₂

Correct option is (C)

In N₂O oxidation states of nitrogen = +1

In NO oxidation states of nitrogen = +2

In N₂O₃ oxidation states of nitrogen = +3

In NO₂ oxidation states of nitrogen = +4

⇒Redox

Topic 2 : Oxidation Number/Oxidation State