The pH of H2SO4 (sulfuric acid) depends on its concentration. Sulfuric acid is a strong acid, meaning it dissociates almost completely in water. Therefore, the pH will be significantly acidic and can range from very low (even negative for highly concentrated solutions) to around 2-3 for dilute solutions.
Here's a breakdown:
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Concentrated H2SO4: Concentrated sulfuric acid (around 18 M) can have a pH well below 0. In fact, it can even have a negative pH value. This is because the pH scale is based on dilute solutions, and at high concentrations, the activity of hydrogen ions (H+) becomes significantly different from their concentration.
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Dilute H2SO4: As the sulfuric acid is diluted, the pH increases. For example, a 0.1 M solution of H2SO4 would have a pH around 1.
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Very Dilute H2SO4: Extremely dilute solutions, such as those found in some industrial processes or diluted laboratory solutions, might have pH values between 2 and 3, as suggested by BYJU'S.
Important Considerations:
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Sulfuric acid is a diprotic acid, meaning it can donate two protons (H+) per molecule. The first dissociation is essentially complete, but the second dissociation might not be complete, especially at higher pH values.
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Calculating the exact pH requires knowing the concentration of the sulfuric acid solution and taking into account the second dissociation constant.
In summary, there isn't a single pH value for H2SO4; it depends entirely on its concentration. It is always a strong acid, though, so its pH will always be less than 7.
