Oxidation number of cobalt in K[Co(CO)₄] is

(1) + 1

(2) + 3

(3) – 1

(4) – 3

The oxidation number of nickel in Ni(CO)₄ :

1. 0

2. + 4

3. – 4

4. + 2

Sn⁺⁺ loses two electrons in a reaction. The final oxidation number of tin will be:

1. + 2

2. Zero

3. + 4

4. – 2

The oxidation number of S in H₂S₂O₈ is:

1. + 2

2. + 4

3. + 6

4. + 7

The oxidation state of nitrogen in N₃H is:

1. $+\frac{1}{3}$

2. + 3

3. –1

4. $-\frac{1}{3}$

The oxidation state of Cr in [Cr(NH₃)₄Cl₂]⁺ is:

1.  +3

2.  +2

3.  +1

4.    0

1. 1

2. 2

3. 3

4. 0

The oxidation number of P in Mg₂P₂O₇ is : 

What is the oxidation number of sulphur in $$
Na₂S₄O₆

Find the oxidation number of cobalt (Co) in the coordination compound [Co(NH₃)₄Cl(NO₂)].

1. +2

2. +3

3. +4

4. +5