Question

In a test, Rashi has to write the chemical equation for the formation of Hydrochloric acid. She wrote

$H_2\left(g\right)+2Cl\left(g\right)\to 2HCl\left(g\right)$

The teacher marked the answer wrong. Why is it so?

• A. The equation is not balanced.
• B. Hydrogen and chlorine do not react to form hydrochloric acid.
• C. In this 2 atoms of chlorine were used insteadof1 molecule of chlorine.
• D. In this 2 molecule of chlorine was used instead of 2 atoms of chlorine.

Answer 1

The correct option is C

In this 2 atoms of chlorine were used insteadof1 molecule of chlorine.

In the above reaction $2Cl$ just means that there are 2 single chlorine atoms These atoms are NOT bonded to each other. The 2 written in $C{l}_2$ means that there are two chlorine atoms covalently bonded to form a chlorine molecule.

The correct equation should be:
$H_2\left(g\right)+C{l}_2\left(g\right)\to 2HCl\left(g\right)$