Let's analyze the given chemical reaction:
[tex]\[
2 HCl (aq) + Ca(OH)_2 (aq) \rightarrow 2 H_2O (l) + CaCl_2 (aq)
\][/tex]
We need to find the best description for the [tex]\( HCl \)[/tex] component in the context of this balanced chemical reaction.
The balanced equation tells us that:
- 2 moles of [tex]\( HCl \)[/tex] react with 1 mole of [tex]\( Ca(OH)_2 \)[/tex].
- Each mole of [tex]\( HCl \)[/tex] consist of [tex]\(6.022 \times 10^{23}\)[/tex] HCl molecules.
Now, let's evaluate each of the given options:
1. 2 L of [tex]\( HCl \)[/tex]:
- The units suggest a volume measurement, which is not specific in describing the quantity of [tex]\( HCl \)[/tex] needed in moles for the reaction. Additionally, without specifying the concentration of [tex]\( HCl \)[/tex], this option is ambiguous.
2. 36.45 g of [tex]\( HCl \)[/tex]:
- This option indicates a mass measurement. The molar mass of [tex]\( HCl \)[/tex] is approximately 36.45 g/mol. Thus, 36.45 g of [tex]\( HCl \)[/tex] corresponds to [tex]\( 1 \)[/tex] mole of [tex]\( HCl \)[/tex]. However, according to the balanced equation, [tex]\( 2 \)[/tex] moles of [tex]\( HCl \)[/tex] are needed.
3. 2 moles of [tex]\( HCl \)[/tex]:
- This matches the 2 moles of [tex]\( HCl \)[/tex] required based on the stoichiometry of the balanced equation. This description is precise and in agreement with the balanced reaction.
4. 2 atoms of [tex]\( HCl \)[/tex]:
- [tex]\( HCl \)[/tex] is a molecule composed of Hydrogen and Chlorine atoms. Describing [tex]\( HCl \)[/tex] as atoms is incorrect because [tex]\( HCl \)[/tex] exists as molecules, not isolated atoms, and 2 atoms do not represent the substance correctly in this reaction context.
Given these evaluations, the most accurate and detailed description for the [tex]\( HCl \)[/tex] component in the balanced chemical reaction is:
2 moles of [tex]\( HCl \)[/tex]
Thus, out of the options provided, the correct one is:
3. 2 moles [tex]\( HCl \)[/tex]
