Oxidation and reduction

Question 1 of 10

What is the oxidation number of sulphur in H₂SO₄?

Question 2 of 10

In the reaction CuO + H₂ → Cu + H₂O, the reducing agent is

Question 3 of 10

In electrolysis, reduction takes place at the

Question 4 of 10

The oxidation number of chromium in K₂Cr₂O₇ is

Question 5 of 10

In the reaction 2H₂S + SO₂ → 3S + 2H₂O, the oxidising agent is

Question 6 of 10

Which is the best oxidising agent?

Question 7 of 10

The standard electrode potential of zinc is −0.76 V and copper +0.34 V. The e.m.f. of a Daniell cell is

Question 8 of 10

Rusting of iron is an example of

Question 9 of 10

Oxidation is

Question 10 of 10

In MnO₄⁻ + 8H⁺ + 5e⁻ → Mn²⁺ + 4H₂O, the change in oxidation number of Mn is