Answer:
4.002 mol is in 68.16 grams of NH3
This problem is providing us with the mass of hydrochloric acid and the volume of solution and asks for the pH of the resulting solution, which turns out to be 1.477.
<h3>pH calculations</h3>
In chemistry, one can calculate the pH of a solution by firstly obtaining its molarity as the division of the moles of solute by the liters of solution, so in this case for HCl we have:

Next, due to the fact that hydrochloric acid is a strong acid, we realize its concentration is nearly the same to the released hydrogen ions to the solution upon ionization. Thereby, the resulting pH is:

Which conserves as much decimals as significant figures in the molarity.
Learn more about pH calculations: brainly.com/question/1195974
Every redox reaction consists of two parts, the oxidation and the reduction. Each one separately is called a half - reaction. During the redox reaction there is a transfer of electrons from the substance being oxidized to the substance being reduced.
In the context of chemistry, yes. Energy input is always equal to the energy output.