Answer:
The answer is in the explanation
Explanation:
Half-life is defined as the time that a substance requires to decrease its concentration in the half of the initial concentration. For example, if we have 1M of a substance X, after 1 half life the concentration is:
1M / 2 = 0.5M
Now, after the second half-life, the concentration would be:
0.5M / 2 = 0.25M
That is the reason why the substance is not totally consumed after two half lives.
