Understanding pH and Indicators

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What is the logarithmic formula for pH?

pH = -log[H⁺], where [H⁺] is the concentration of hydrogen ions in mol/L.

Why is lemon juice acidic?

Lemon juice contains citric acid, which increases the concentration of hydrogen ions.

What role do buffers play in maintaining pH?

Buffers resist changes in pH by neutralizing added acids or bases.

What is the pH range for most biological fluids?

Most biological fluids have pH ranges from 6 to 8.

Name a common natural pH indicator.

Red cabbage juice is a common natural pH indicator.

What is the bromothymol blue color change from acid to base?

Bromothymol blue changes from yellow in acidic conditions to blue in basic conditions.

What is the endpoint in a titration?

The endpoint is when the indicator changes color, signaling that the titration is complete.

Why are universal indicators useful?

Universal indicators provide a full range of color changes over the entire pH scale, indicating the acidity or basicity of a solution.

What color does phenolphthalein turn in a basic solution?

Phenolphthalein turns pink in a basic solution.

How can pH be measured digitally?

pH can be measured using a pH meter.

What happens to pH when a base is added to an acidic solution?

The pH increases as the acidic solution becomes less acidic.

Why do weak acids only partially dissociate in water?

Weak acids only partially dissociate due to the existence of equilibrium, favoring the undissociated form.

How does temperature affect pH?

Temperature can affect pH measurements; generally, increased temperature can decrease the pH of a neutral water solution.

What is the effect of dilution on the pH of a strong acid?

Dilution of a strong acid increases its pH, making it less acidic.

What is a common use of acids in the food industry?

Acids like citric acid are used as preservatives and to add tartness to foods.