Answer:

3Br2(l)+5KClO3(aq)+3H2O(l)→6HBrO3(aq)+5KCl(aq)

(a) Reducing agent = Br2

(b) Oxidizing agent = KClO3

(c) Substance being oxidized = Br2

(d) Substance gaining electrons = Cl atom in KClO3

(e) Substance being reduced = KClO3

(f) Substance losing electrons = Br

Step-by-step explanation

First identify oxidation number for atoms on the left and right

Left;

Br2 = 0

K = +1

Cl = +5

O3 = -6

Right

Br = +5

O3 = -6

K = + 1

Cl = - 1

Then find the changes in oxidation numbers for the atoms

Cl = +5 --> -1 hence change = -6

Br = 0 --> +5 hence change = +5

Make the total increase in oxidation number equal the total decrease in oxidation number, this means

You multiply 5 by Cl atoms or 6 by Br atom and this gives us a total changes of +30 and -30. Place these numbers (5 and 6) as coefficients of Cl and Br and balance the other atoms as below.

3Br2(l)+5KClO3(aq)+3H2O(l)→6HBrO3(aq)+5KCl(aq)

 

Oxidation results in the increase in oxidation number while reduction results in decrease in oxidation. This means the species whose oxidation number increases has been oxidized while that whose oxidation number decreases has been reduced. The reduced species becomes oxidizing agent as it causes oxidation on the other species which loses electrons to it. While oxidized species becomes the reducing agent as it causes reduction on the other species which gains its electrons.

A loss in electrons results in more positive charge on a species. Hence the oxidation number changes from a less positive to a more positive and this species is said to be oxidized as oxidation number is increasing.

A gain of electrons results in a more negative charge on a species. Hence the oxidation number changes from a less negative to a more negative and mathematically it is decreasing and hence species is said to be reduced.

Therefore in this case the substance gaining electrons is Cl atom in KClO3 while that losing electrons is Br