To understand what happens when the concentration of hydrogen chloride (HCl) molecules is doubled in the reaction between calcium carbonate (CaCO₃) and HCl, we need to consider the principles of chemical kinetics, particularly the collision theory.
The reaction we are examining is:
[tex]\[ \text{CaCO}_3 + 2 \text{HCl} \rightarrow \text{CaCl}_2 + \text{CO}_2 + \text{H}_2\text{O} \][/tex]
### Step-by-Step Explanation:
1. Collision Theory:
- The rate of a chemical reaction depends on the frequency and effectiveness of collisions between reactant molecules.
- For a reaction to occur, reactant molecules must collide with sufficient energy and proper orientation.
2. Effect of Concentration on Collision Frequency:
- According to the collision theory, increasing the concentration of a reactant increases the number of molecules in a given volume.
- This leads to an increased number of collisions per unit time because there are more molecules available to collide with one another.
3. Specifics for Doubling HCl Concentration:
- In our reaction, if we double the concentration of HCl, we effectively double the number of HCl molecules available to interact with CaCO₃.
- With more HCl molecules present, the frequency of collisions between HCl and CaCO₃ molecules will increase.
4. Impact on Reaction Rate:
- As the number of effective collisions (those that lead to a reaction) increases, the rate at which the reactants are converted into products also increases.
- Therefore, doubling the HCl concentration increases the rate of the forward reaction.
### Summary:
When the concentration of hydrogen chloride (HCl) molecules is doubled, the number of collisions between the reactants increases, which causes the rate of the forward reaction to increase.
