Question

Which of the following reactions are redox reactions? Check all that apply. Check all that apply. Al(s)+3A g + (aq)→A l 3+ (aq)+3Ag(s) S O 3 (g)+ H 2 O(l)→ H 2 S O 4 (aq) Ba(s)+C l 2 (g)→BaC l 2 (s) Mg(s)+B r 2 (l)→MgB r 2 (s)

Answer 1

Redox reactions are the reactions where oxidation and reduction occurs simultaneously in one single reaction.

Oxidation involves loss of electrons so if there is an increase in oxidation number of an element on moving from reactant to product side, it is called oxidation.

Reduction involves gain of electrons so if there is a decrease in oxidation number of an element on moving from reactant to product side, it is called reduction.

A reaction will be redox reaction if one species gets oxidised and other gets reduced in a reaction .

The following rules will be used to write oxidation number of each element :

1. The oxidation number of elements in their native state is zero.

2. The oxidation number of oxygen in most of its compounds is -2.

3. The oxidation number of hydrogen in its compounds is +1.

4. The oxidation number of halogens ( F, Cl, Br, I) in their compounds is -1.

5. The oxidation numbers of all elements combined should be equal to the total oxidation state of the whole molecule.