Question

What does electron affinity measure?Why must oxidation be accompanied by a reduction? How does one determine the relative reactivities of metals?

Answer 1

how fast atom gain electron is measured by electron affinity

the energy released when electron added to atom is called electron affinity.

oxidation means loosing electrons

if any atom loosing elecreons those electrons must be gained by other atom

the gaining electron is reduction.

so when enevr there is oxidation there must be reduction also.

reactivity of etals determined experimentally.

suppose to the solution with metal salt a piece of metal is added if this metal reacts with metal salt then added metal is more reactive than metal present in salt. in such way we deside the relative reactivity of metals.