Question

What happens when Hydrochloric acid reacts with metals;
A) Hydrogen gas
B) Chlorine gas
C) Carbon dioxide
D) Oxygen gas

Answer 1

Hydrochloric acid is a Lewis acid, which accepts a bonding pair of electrons, and metal is electropositive in nature which means a metal will try to donate electrons to exist in ${{\text{M}}^{{\text{n}} + }}$, where $M$ represents a metal atom and the value of $'n'$ usually ranges from $1 - 7$.

Complete answer:
So, we know the position of metals in a periodic table, they reside on the left side, and as we go along the period metallic character decreases. Hence, most nonmetals are on the right side of the table and Chlorine is also a non-metal.
When a metal of s-block reacts with acids it forms a metal salt and releases hydrogen gas, like in the case of $HCl$, the following reaction takes place;
${\text{M + 2HCl}} \to {\text{ MC}}{{\text{l}}_2}{\text{ + }}{{\text{H}}_2}(g)$
Where ‘M’ represents metal.
The formation of Hydrogen gas can be confirmed by the pop sound.

Hence, the correct answer option is (A) i.e. Hydrogen gas.

Additional information: Metals are more reactive than Hydrogen, as they are placed above the hydrogen in the reactivity series, and the reaction that occurs is termed as a single displacement reaction. A single displacement reaction is a chemical reaction in which one element is generally replaced by another in a chemical compound.

Note: Although hydrogen gas, not piousness, but inhaling a very high concentration ($135ppm$) for about $30$ minutes can be lethal. Hydrogen has the ability to replace oxygen in our body, this can cause hypoxia, a condition of lower concentration of oxygen, which alters bodily function.