Unit 09 Post Assessment Remediation (PAR)

Which compound yields H⁺ ions as the only positive ions in an aqueous solution?

• KOH

• NaOH

• CH₃OH

• CH₃COOH

Given the balanced equation representing a reaction: NH₃(g) + H₂O(ℓ) ⇌ NH₄⁺(aq) + OH⁻(aq). According to one acid-base theory, the NH₃(g) molecules act as

• an acid because they accept H⁺ ions

• an acid because they donate H⁺ ions

• a base because they accept H⁺ ions

• a base because they donate H⁺ ions

Solution A has a pH value of 2.0 and solution B has a pH value of 4.0. How many times greater is the hydronium ion concentration in solution A than the hydronium ion concentration in solution B?

• 10

• 2

• 100

• 4

Which indicator would best distinguish between a solution with a pH of 3.5 and a solution with a pH of 5.5?

• bromthymol blue

• bromcresol green

• litmus

• thymol blue

The table below shows the color of the indicators methyl orange and bromthymol blue in two samples of the same solution. Results of Acid-Base Indicator Tests. Which pH value is consistent with the indicator results?

• 1

• 5

• 3

• 10

Tags

NGSS.MS-PS1-2

Which solution when mixed with a drop of bromthymol blue will cause the indicator to change from blue to yellow?

• 0.1 M HCl

• 0.1 M NH₃

• 0.1 M CH₃OH

• 0.1 M NaOH

If an aqueous solution turns blue litmus red, which relationship exists between the hydronium ion and hydroxide ion concentrations?

• [H₃O⁺] > [OH⁻]

• [H₃O⁺] < [OH⁻]

• [H₃O⁺] = [OH⁻] = 10⁻⁷

• [H₃O⁺] = [OH⁻] = 10⁻¹⁴

Which two compounds are electrolytes?

• KOH and CH₃COOH

• KOH and C₅H₁₂

• CH₃OH and CH₃COOH

• CH₃OH and C₅H₁₂

An example of a nonelectrolyte is

• C₆H₁₂O₆(aq)

• K₂SO₄(aq)

• NaCl(aq)

• HCl(aq)

Which of these pH numbers indicates the highest level of acidity?

• 5

• 8

• 10

• 12