（c)A student is given an aqueous solution of chlorine and an aqueous solution of potassium bromide.
Explain how he can use these two solutions to compare the reactivity of chlorine
with the reactivity of bromine.

By using periodic table.

Explanation:

By using periodic table the student can find out that which atom is more reactive because the arrangement of atoms on the periodic table occurs on the atomic number that shows the reactivity of atoms. Chlorine and bromines are members of same family but the chlorine is present above bromine in the group due to less atomic number. The reactivity of chlorine solution is higher than bromine solution due to unstable radical of chlorine.

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