Understanding the pH Scale

What is the pH scale and what does it measure?

• The pH scale indicates the presence of carbon dioxide in water.

• The pH scale measures temperature in a solution.

• The pH scale measures the concentration of hydrogen ions in a solution, indicating its acidity or alkalinity.

• The pH scale measures the density of a liquid.

How is pH calculated from hydrogen ion concentration?

• pH = [H+]^2

• pH = 14 - [H+]

• pH = log10[H+]

• pH = -log10[H+]

What is the pH of a neutral solution at 25°C?

• 7

• 6

• 5

• 8

If a solution has a pH of 3, is it acidic, basic, or neutral?

• basic

• alkaline

• acidic

• neutral

What is the relationship between pH and the concentration of hydrogen ions?

• pH is inversely related to the concentration of hydrogen ions; as H+ concentration increases, pH decreases.

• pH increases as the concentration of hydrogen ions increases.

• pH is directly proportional to the concentration of hydrogen ions.

• pH has no relationship with the concentration of hydrogen ions.

How does the pH scale range from 0 to 14 relate to acidity and basicity?

• The pH scale ranges from 0 to 20, where 0-5 indicates acidity, 10 is neutral, and 11-20 indicates basicity.

• The pH scale ranges from 0 to 14, where 0-6 indicates acidity, 7 is neutral, and 8-14 indicates basicity.

• The pH scale ranges from 0 to 14, where 0-4 indicates basicity, 5-9 is neutral, and 10-14 indicates acidity.

• The pH scale ranges from 1 to 10, where 1-3 indicates acidity, 4-7 is neutral, and 8-10 indicates basicity.

What is the pH of a solution with a hydrogen ion concentration of 1 x 10^-7 M?

• 6

• 10

• 8

• 7

How do buffers work to maintain pH levels in a solution?

• Buffers change the pH of a solution permanently.

• Buffers only work in acidic solutions.

• Buffers maintain pH levels by neutralizing added acids or bases through equilibrium reactions between weak acids and their conjugate bases.

• Buffers are only effective in solid substances.

What is the significance of a pH of 7.4 in biological systems?

• A pH of 7.4 indicates a state of acidosis.

• A pH of 7.4 is significant as it is the normal physiological pH for human blood, essential for proper biological functions.

• A pH of 7.4 is too acidic for human blood.

• A pH of 7.4 is the optimal level for plant growth.

How can you change the pH of a solution?

• Use a thermometer to measure temperature

• Add water to dilute the solution

• Stir the solution vigorously to mix it

• Add an acid to lower pH or a base to raise pH.