Which of the following is an observable property of many acids?

A. They become slippery when reacting with water.
Incorrect. This is a property of bases.

B. They react with metals to release hydrogen gas.
Correct! Acids react with metals.

C. They produce salts when mixed with other acids.
Incorrect. They produce salts when mixed with bases.

D. They become more acidic when mixed bases.
Incorrect. Acidic solutions become less acidic when mixed with bases.

Which one of the following laboratory solutions would have the highest acidity?

A. pH of 11
Incorrect. pH of 11 would be a basic solution.

B. pH of 7
Incorrect. pH of 7 is neutral.

C. pH of 5
Incorrect. Although this solution is acidic, the most acidic will have a lower pH.

D. pH of 3
Correct! This is most acidic solution.

The water from hot springs near the Ebeko volcano in the Pacific Ocean has a very low pH. Low pH indicates which of the following about the water?

A. It has no detectable H+ or OH- ions.
Incorrect. Any solution that contains water will have some amount of H+ and OH-.

B. It has equal concentrations of H+ and OH- ions.
Incorrect. If these concentrations were equal, it would be neutral with a pH of 7.

C. It has high concentrations of H+ ions.
Correct! Acidic solutions have higher concentrations of H+.

D. It has equal numbers of positive and negative ions.
Incorrect. pH measures the concentration of H+.

Which of the following solutions has the highest concentration of H+?

A. Bleach (pH 13)
Incorrect. Bleach is a base.

B. Water (pH 7)
Incorrect. Water is neutral.

C. Tomato Juice (pH 4)
Incorrect. This is an acid, but it does not have the highest concentration of H+.

D. Vinegar (pH 3)
Correct! The lower the pH value, the higher the concentration of hydrogen ions.

Phenolphthalein is an indicator that turns pink when added to a basic solution. Which of the following would turn phenolphthalein pink?

A. NaOH
Correct! NaOH is a base.

B. HCl
Incorrect. HCl is an acid.

C. H₂O
Incorrect. Water is neutral.

D. NaCl
Incorrect. This is an ionic compound that does not contain OH-.