Question

select the correct answer.
which gas is produced when mg(s) is added to hcl(aq)?
o a. o2
o b. h2
o c. cl2
o d. co2

Explanation:

Step1: Write the chemical reaction

When \(Mg(s)\) reacts with \(HCl(aq)\), the reaction is \(Mg + 2HCl=MgCl_2 + H_2\uparrow\).

Step2: Analyze the products

In this single - displacement reaction, magnesium displaces hydrogen from hydrochloric acid. The products are magnesium chloride (\(MgCl_2\)) and hydrogen gas (\(H_2\)). There is no oxygen or carbon in the reactants (\(Mg\) and \(HCl\)), so \(O_2\) (option A) and \(CO_2\) (option D) cannot be formed. Chlorine in \(HCl\) is in the form of chloride ions (\(Cl^-\)) and is not oxidized to \(Cl_2\) in this reaction (since \(Mg\) is oxidized and \(H^+\) is reduced). So \(Cl_2\) (option C) is not formed.

Answer:

B. \(H_2\)