Question

hydrogen chloride (hcl) dissolved in water can be used to remove rust and limescale from pipes. it is produced when hydrogen gas ($h_2$) and chlorine gas ($cl_2$) are mixed and heated. which model accurately represents this reaction?

Explanation:

Step1: Write balanced reaction equation

The chemical reaction is $\ce{H_{2} + Cl_{2} -> 2HCl}$

Step2: Match to particle model

1 molecule of $\ce{H_{2}}$ (2 small gray spheres) reacts with 1 molecule of $\ce{Cl_{2}}$ (2 large green spheres) to form 2 molecules of $\ce{HCl}$ (1 gray + 1 green sphere bonded).

Answer:

The third model (from left to right, the box with 1 $\ce{H_{2}}$ molecule, 1 $\ce{Cl_{2}}$ molecule, and 2 $\ce{HCl}$ molecules as products) accurately represents this reaction.