When MnO₂ is fused with KOH, a colouredcompound is formed. The product and its colour is:

• K₂MnO₄ , purple colour

• Mn₂O₃ , brown

• Mn₂O₄ , black

• KaMnO₄ , purple

22.

In [NiCl₄]^2-, the number of unpaired electrons, are

• 4

• 2

• 3

• 5

H₂C₂O₄ + KMnO₄ in acidic medium reacts to have change in oxidation number of Mn from

• 7 to 5

• 2 to 7

• 5 to 7

• 7 to 2

Oxidation number Fe in K₃ [FeCN)₆] is

• +1

• +2

• +3

• +4

Oxidation number of Cr in K₂Cr₂O₇ is

• 2

• 4

• 6

• 7

Which of the following is most powerful oxidising agent?

• I₂

• Cl₂

• Br₂

• F₂

Strongest Bronsted base among the following anions is

• Cl${\mathrm{O}}_4^{-}$

• Cl${\mathrm{O}}_3^{-}$

• Cl${\mathrm{O}}_2^{-}$

• ClO^-

The colourless species is

• VCl₃

• VOSO₄

• Na₃VO₄

• [V(H₂O)₆]SO₄.H₂O

For which of the following elements it is difficult to disproportionate in +3 oxidation state ?

• N

• As

• Sb

• Bi

Substances that are oxidised and reduced in the following reaction are respectively

N₂H₄ (l) + 2H₂O₂ (l) $\to$N₂ (g) + 4H₂O (l)

• N₂H₄, H₂O

• N₂H₄, H₂O₂

• N₂, H₂O₂

• H₂O, N₂