Assertion : Cu is stronger reducing agent than H₂.

Reason : E° of Cu²⁺/Cu is negative.

• If both assertion and reason are true and reason is the correct explanation of assertion.

• If both assertion and reason are true but reason is not the correct explanation of assertion.

• If assertion is true but reason is false.

• If both assertion and reason are false.

When KMnO₄ reacts with KBr in alkaline medium gives bromate ion. Then oxidation state of Mn changes from +7 to

• +6

• +4

• +3

• +2

Assertion : Chlorine undergoes disproportionation reaction in alkaline medium.

Reason : Cl₂ is an oxidising agent.

• If both assertion and reason are true and reason is the correct explanation of assertion

• If both assertion and reason are true but reason is not the correct explanation of assertion

• If assertion is true but reason is false

• If both assertion and reason are false.

Assertion : The formal oxidation no. of sulphur in Na₂S₄O₆ is 2.5.

Reason : Two S-atoms are not directly linked with O-atoms.

• If both assertion and reason are true and reason is the correct explanation of assertion

• If both assertion and reason are true but reason is not the correct explanation of assertion

• If assertion is true but reason is false

• If both assertion and reason are false

Which of the following elements shows +4 oxidation state?

• Sn

• Ra

• Fr

• Sc

The correct order of stability of the superoxides is

• KO₂ > RbO₂ > CsO₂

• KO₂ > CsO₂ > RbO₂

• CsO₂ > RbO₂ > KO₂

• RbO₂ > CsO₂ > KO₂

The charge required for the reduction of 1 mol of ${\mathrm{MnO}}_4^{-}$  to MnO₂ is

• 1 F

• 2 F

• 3 F

• 6 F

In the balanced chemical reaction
IO_3^- + aI^- + bH⁺ → cH₂O + dI₂
a, b, c and d respectively corresponds to

• 5, 6, 3, 3

• 5, 3, 6, 3

• 3, 5, 3, 6

• 5, 6, 5, 5

129.

Among the following pairs of ions, the lower oxidation state in aqueous solution is more stable than the other, in

• Tl⁺, Tl³⁺

• Cu⁺, Cu²⁺

• Cr²⁺, Cr³⁺

• V²⁺, VO²⁺

The oxidation number of carbon in CH₂O is :

• - 2

• + 2

• 0

• + 4