Table of contents

1. Intro to General Chemistry3h 48m
2. Atoms & Elements4h 16m
3. Chemical Reactions4h 10m
4. BONUS: Lab Techniques and Procedures1h 38m
5. BONUS: Mathematical Operations and Functions48m
6. Chemical Quantities & Aqueous Reactions3h 53m
7. Gases3h 49m
8. Thermochemistry2h 37m
9. Quantum Mechanics2h 58m
10. Periodic Properties of the Elements3h 9m
11. Bonding & Molecular Structure3h 29m
12. Molecular Shapes & Valence Bond Theory1h 57m
13. Liquids, Solids & Intermolecular Forces2h 23m
14. Solutions3h 1m
15. Chemical Kinetics2h 53m
16. Chemical Equilibrium2h 29m
17. Acid and Base Equilibrium5h 1m
18. Aqueous Equilibrium4h 47m
19. Chemical Thermodynamics1h 50m
20. Electrochemistry2h 42m
21. Nuclear Chemistry2h 36m
22. Organic Chemistry5h 7m
23. Chemistry of the Nonmetals2h 39m
24. Transition Metals and Coordination Compounds3h 16m

17. Acid and Base Equilibrium

pH of Strong Acids and Bases

General Chemistry

17. Acid and Base Equilibrium

pH of Strong Acids and Bases

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Multiple Choice

Find the pH of a 0.031 M H2SO4 (aq) solution at 25 degrees Celsius. Ka for HSO4- is 1.2 × 10^-2.

1.20

1.50

2.00

0.85

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Verified step by step guidance

Start by recognizing that sulfuric acid (H2SO4) is a strong acid, which means it dissociates completely in its first ionization step: H2SO4 → H+ + HSO4-. Therefore, the initial concentration of H+ ions from the first dissociation is equal to the concentration of H2SO4, which is 0.031 M.

Next, consider the second ionization step of HSO4-, which is a weak acid: HSO4- ⇌ H+ + SO4^2-. Use the given Ka value for HSO4- (1.2 × 10^-2) to determine the additional concentration of H+ ions produced from this equilibrium.

Set up an equilibrium expression for the second ionization: Ka = [H+][SO4^2-] / [HSO4-]. Assume that the change in concentration of HSO4- is 'x', which is also the change in concentration of H+ and SO4^2-.

Substitute the known values into the equilibrium expression: 1.2 × 10^-2 = (0.031 + x)(x) / (0.031 - x). Solve for 'x' to find the additional concentration of H+ ions from the second ionization.

Finally, calculate the total concentration of H+ ions by adding the concentration from the first ionization (0.031 M) to the additional concentration 'x' from the second ionization. Use the formula for pH: pH = -log[H+], to find the pH of the solution.