N the following reaction: Mg(s) + 2HCl(aq) → MgCl2(aq) + H2(g) A. H2 is the reducing agent and is oxidized B. HCl is reduced and is the oxidizing agent C. MgCl2 is the oxidizing agent and is reduced D. Mg is reduced and is the oxidizing agent. E. HCl is oxidized and is the reducing agent Reset Selection

HCl is reduced and is the oxidizing agent

Explanation:

Looking at the reaction shown in the question

Mg(s) + 2HCl(aq) → MgCl2(aq) + H2(g)

HCl is reduced to H2. The oxidation number of hydrogen decreased from +1 to zero. While magnesium was oxidized. Its oxidation number increased from zero to +2.

Hence we can rightly say that HCl was the oxidizing agent since the oxidizing agent is reduced in a reaction and the reducing agent is oxidized in a reaction.

first one is the correct answer

the formula mass of a molecule or a compound is the sum of the atomic weights of the atoms in its empirical formula

(that's what i know about formula mass)