Chemistry · Acids, Bases and Salts
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The pH of 10-3 M H2SO4 solution is:
- A3.0
- B2.7
- C2.0
- D1.5
To determine the pH of a 10-3 M H2SO4 solution, recognize that H2SO4 is a strong acid that completely dissociates into 2 H+ and SO42-. Thus, the concentration of H+ ions is twice the initial concentration of H2SO4, which is 2 x 10-3 M. The pH is calculated using the formula: pH = -log[H+]. Substituting the concentration, we get pH = -log(2 x 10-3) = 3 - log(2) ≈ 2.7. Hence, the correct answer is 2.7. The other options result from incorrect calculations or misunderstandings of the relationship between H2SO4's dissociation and pH.
This pH calculation doesn't account for the fact that each molecule of H2SO4 produces two H+ ions, doubling the concentration of H+ ions.
This is correct. After full dissociation, the concentration of H+ ions is 2 x 10-3 M, leading to a pH = -log(2 x 10-3) = 2.7.
This assumes incorrect initial concentration or incorrect ionization process, ignoring the logarithmic nature of pH calculation.
This value is too low and results from overestimating the concentration of H+ ions or misunderstanding the pH scale.
Tagged under Chemistry · Acids, Bases and Salts · 2019