Answer :
To determine which option best describes the reaction given by [tex]\( \text{H}_2(g) + \text{Cl}_2(g) \rightarrow 2 \text{HCl}(g) \)[/tex] with [tex]\( \Delta H = -184.6 \, \text{kJ/mol} \)[/tex], let's analyze the provided information step by step.
1. Understanding [tex]\( \Delta H \)[/tex] (Enthalpy Change):
- The given reaction has an enthalpy change [tex]\( \Delta H \)[/tex] of -184.6 kJ/mol.
- The negative sign in [tex]\( \Delta H \)[/tex] indicates that the reaction releases energy in the form of heat.
2. Interpreting Exothermic vs. Endothermic:
- A negative [tex]\( \Delta H \)[/tex] means the reaction is exothermic.
- Exothermic reactions release heat to the surroundings.
- Conversely, endothermic reactions have a positive [tex]\( \Delta H \)[/tex] and absorb heat from the surroundings.
3. Analyzing the Options:
- Option A: The reaction has no activation energy. This is incorrect because all chemical reactions require some activation energy to proceed, even exothermic ones.
- Option B: The reaction produces heat. This is correct because an exothermic reaction releases heat, as indicated by the negative [tex]\( \Delta H \)[/tex].
- Option C: The reaction requires heat. This is incorrect, as that would describe an endothermic reaction with a positive [tex]\( \Delta H \)[/tex].
- Option D: The reaction is endothermic. This is incorrect, as an endothermic reaction would have a positive [tex]\( \Delta H \)[/tex].
Based on the analysis, the correct choice is:
B. The reaction produces heat.
1. Understanding [tex]\( \Delta H \)[/tex] (Enthalpy Change):
- The given reaction has an enthalpy change [tex]\( \Delta H \)[/tex] of -184.6 kJ/mol.
- The negative sign in [tex]\( \Delta H \)[/tex] indicates that the reaction releases energy in the form of heat.
2. Interpreting Exothermic vs. Endothermic:
- A negative [tex]\( \Delta H \)[/tex] means the reaction is exothermic.
- Exothermic reactions release heat to the surroundings.
- Conversely, endothermic reactions have a positive [tex]\( \Delta H \)[/tex] and absorb heat from the surroundings.
3. Analyzing the Options:
- Option A: The reaction has no activation energy. This is incorrect because all chemical reactions require some activation energy to proceed, even exothermic ones.
- Option B: The reaction produces heat. This is correct because an exothermic reaction releases heat, as indicated by the negative [tex]\( \Delta H \)[/tex].
- Option C: The reaction requires heat. This is incorrect, as that would describe an endothermic reaction with a positive [tex]\( \Delta H \)[/tex].
- Option D: The reaction is endothermic. This is incorrect, as an endothermic reaction would have a positive [tex]\( \Delta H \)[/tex].
Based on the analysis, the correct choice is:
B. The reaction produces heat.
