# Sodium metal reacts with hydrochloric acid to produce salt and hydrogen gas. What are the reactants in this chemical reaction?

Aug 2, 2016

Sodium metal and hydrochloric acid.

#### Explanation:

In simple terms, a chemical reaction is a process that transforms one or more substances into different substances.

The substances that are being transformed are called reactants and the substances that are being produced are called products.

Notice that the problem provides you with the following information

Sodium metal reacts with hydrochloric acid to produce salt and hydrogen gas.

You can thus say that in this chemical reaction, two substances react

• sodium metal, ${\text{Na}}_{\left(s\right)}$
• hydrochloric acid, ${\text{HCl}}_{\left(a q\right)}$

and two substances are produced

• salt, i.e. sodium chloride, ${\text{NaCl}}_{\left(a q\right)}$
• hydrogen gas, ${\text{H}}_{2 \left(g\right)}$

This means that your reactants will be sodium metal and hydrochloric acid, since these are the substances that are being transformed to form salt and hydrogen gas.

To write a balanced chemical equation that describes this single replacement reaction, remember that

• the reactants are added to the left of the reaction arrow
• the products are added to the right of the reaction arrow

You will thus have

overbrace("Na"_ ((s)) + "HCl"_ ((aq)))^(color(blue)("reactants")) -> overbrace("NaCl"_ ((aq)) + "H"_ (2(g)))^(color(darkgreen)("products"))
$\textcolor{w h i t e}{a a a a a a a a a a a a \frac{a}{a}} \textcolor{red}{\uparrow}$
$\textcolor{w h i t e}{a a a a a a a a a a} \textcolor{red}{\text{reaction arrow}}$

The balanced chemical equation looks like this

$2 {\text{Na"_ ((s)) + 2"HCl"_ ((aq)) -> 2"NaCl"_ ((aq)) + "H}}_{2 \left(g\right)}$