hydrochloric acid 0.2 mixture? a \( 0.18 \mathrm{M}, \mathrm{P}^{\mathrm{H}}=0.2 \) b \( 0.625 \mathrm{M}, \mathrm{P}^{\mathrm{H}}=1.3 \) C \( 0.105 \mathrm{M}, \mathrm{P}^{\mathrm{H}}=0.7 \) d \( 0.450 \mathrm{M}, \mathrm{P}^{\mathrm{H}}=0.3 \)

It appears you're asking which of the given mixtures corresponds to a hydrochloric acid (HCl) solution with a concentration of **0.2 M**. Let's analyze each option based on the relationship between concentration and pH for a strong acid like HCl. ### Understanding the Relationship Hydrochloric acid (**HCl**) is a **strong acid**, meaning it dissociates completely in water: \[ \text{HCl} \rightarrow \text{H}^+ + \text{Cl}^- \] The **pH** of the solution is calculated using the formula: \[ \text{pH} = -\log[\text{H}^+] \] For a **0.2 M** HCl solution: \[ [\text{H}^+] = 0.2 \, \text{M} \] \[ \text{pH} = -\log(0.2) \approx 0.7 \] ### Analyzing the Options | **Option** | **Concentration (M)** | **pH** | **Analysis** | |------------|-----------------------|--------|--------------| | **a)** | 0.18 | 0.2 | For pH 0.2, \([H^+] \approx 0.63 \, \text{M}\). This doesn't match 0.18 M. | | **b)** | 0.625 | 1.3 | For pH 1.3, \([H^+] \approx 0.05 \, \text{M}\). This doesn't match 0.625 M. | | **c)** | 0.105 | 0.7 | For pH 0.7, \([H^+] \approx 0.2 \, \text{M}\). This is closest to the desired concentration when considering significant figures and possible dilution. | | **d)** | 0.450 | 0.3 | For pH 0.3, \([H^+] \approx 0.50 \, \text{M}\). This doesn't match 0.450 M exactly but is in the ballpark. | ### **Best Match: Option c** **Option c** lists a concentration of **0.105 M** with a **pH of 0.7**. While the \([H^+]\) concentration for pH 0.7 should ideally be **0.2 M**, this option is the closest match among the provided choices when considering possible measurement tolerances or dilution factors. ### **Conclusion** **Option c** is the most appropriate choice, as it best aligns with the expected pH for a 0.2 M HCl solution. **Answer:** Option **c** (\( 0.105 \mathrm{M} \), pH = 0.7) is the mixture corresponding to 0.2 M hydrochloric acid.