The answer is A because latent heat is the heat released or absorbed by a body or a thermodynamic system during a constant temperature process.
an example is like melting ice or boiling water. these are example's but like i said the answer is A.
Answer:

Explanation:
Hello,
In this case, for the calculation of the half-life for the mentioned reaction we first must realize that considering the units of the rate constant and the form of the rate law, it is a second-order reaction, therefore, the half-life expression is:
![t_{1/2}=\frac{1}{k[A]_0}](https://tex.z-dn.net/?f=t_%7B1%2F2%7D%3D%5Cfrac%7B1%7D%7Bk%5BA%5D_0%7D)
Therefore, we obtain:

Regards.
You are probably suppose to subtract the two numbers hope that helps.
I think it is A. produces the hydrogen ion