Unit 14 Review R

If a solution has a very low pH, the hydroxide concentration is _______.
Hint: Remember that pH and hydroxide concentration are inversely related.

• very high

• very low

• zero

A solution with pH 8 is a stronger base than a solution at pH 13.

• True

• False

Based on the results of testing colorless solutions with indicators, which solution is most acidic?

Hint: Consider the pH range where each indicator changes color. The more acidic a solution, the lower its pH.

• solution where bromthymol blue is blue

• solution where bromcresol green is blue

• solution where phenolphthalein is pink

• solution where methyl orange is red

Tags

NGSS.MS-PS1-2

Which indicator is yellow in a solution with a pH of 9.8?

Indicators are substances that change color at a specific pH range, allowing us to determine the acidity or basicity of a solution. Each indicator has a distinct color change range, and the color observed depends on the pH of the solution.

Hint: Consider the pH range where the indicator changes color and what color it would be at a pH of 9.8.

• methyl orange

• bromthymol blue

• bromcresol green

• thymol blue

Reorder the following from lowest to highest pH

• Weak Acid

• Strong Base

• Strong Acid

• Neutral

• Weak Base

Match the following

• NaCl

• Acid

• NaOH

• Neutral

• HCl

• Base

The table shows the pH of several solutions. Which solution has the greatest concentration (amount) of H⁺ ions?

Consider that pH is a measure of the hydrogen ion concentration in a solution. A lower pH value indicates a higher concentration of H⁺ ions, while a higher pH value indicates a lower concentration of H⁺ ions.

Hint: Look for the solution with the lowest pH value.

• vinegar

• milk

• water

• bleach

Answer explanation

Remember H⁺ is another name for an acid. So, another way to ask this would be; which of these is the strongest acid?

The table shows the pH of several solutions. Which solution has the greatest concentration (amount) of OH^- ions?

Consider the pH scale, where lower pH values indicate acidic solutions and higher pH values indicate basic solutions. The concentration of OH^- ions increases as the pH value increases.

Hint: Look for the solution with the highest pH value, as it will have the greatest concentration of OH^- ions.

• vinegar

• milk

• water

• bleach

Answer explanation

Remember OH^- is another name for a base. So, another way to ask this would be: which of these is the strongest base?

Match the following

• acid

• 10

• neutral

• salt

• base

• 5

What is the conjugate base of HF?

When an acid donates a proton, the species that remains is called its conjugate base. Consider the dissociation of HF in water and identify the species that results from the loss of a proton.

Hint: Think about what happens to HF when it loses a proton (H⁺).

• H₂F

• H₂F⁺

• F

• F^-