Chemistry Acid-Base Concepts Quiz

Questions and Answers

Of the following, (blank) is a weak acid.

Which of the following is the weakest acid?

HNO2 (Ka = 4.5x10^-4)

Acetic Acid (Ka = 1.8x10^-5)

HF (Ka = 6.8x10^-4)

HClO (Ka = 3.0x10^-8)

HCN (Ka = 4.9x10^-10) (correct)

Classify the following compounds as weak acids (W) or strong acids (S): nitrous acid, hydrochloric acid, hydrofluoric acid.

SSS

WSW (correct)

WSS

WWW

SWW

A- is a weak base. Which equilibrium corresponds to the equilibrium constant Ka for HA?

HA(aq) + H2O(l) H3O+(aq) + A-(aq) Signup and view all the answers

Which of the following ions will act as a weak base in water?

ClO- Signup and view all the answers

Using the data in the table, which of the conjugate bases below is the weakest base?

F- Signup and view all the answers

Using the data in the table, which of the following conjugate acids below is the strongest acid?

H2S Signup and view all the answers

Of the following substances, an aqueous solution of (blank) will form basic solutions?

NaF, K2CO3 Signup and view all the answers

A 0.1 M solution of (blank) has a pH of 7.0.

NaNO3 Signup and view all the answers

What is the conjugate acid of NH3?

NH4+ Signup and view all the answers

Which one of the following pairs cannot be mixed together to form a buffer solution?

NaCl, HCl Signup and view all the answers

What change will be caused by the addition of a small amount of HCl to a solution containing fluoride ions and hydrogen fluoride?

The concentration of fluoride ion will decrease and the concentration of hydrogen fluoride will increase. Signup and view all the answers

In a solution, when the concentrations of a weak acid and its conjugate base are equal, (blank).

The -log of the [H+] and the -log of the Ka are equal. Signup and view all the answers

The addition of hydrofluoric acid and (blank) to water produces a buffer solution.

NaOH Signup and view all the answers

Which of the following could be added to a solution of sodium acetate to produce a buffer?

Acetic acid or hydrochloric acid Signup and view all the answers

Which of the following could be added to a solution of acetic acid to prepare a buffer?

Sodium acetate or sodium hydroxide Signup and view all the answers

Which compound listed below has the greatest molar solubility in water?

CaF2 Signup and view all the answers

Which compound listed below has the smallest molar solubility in water?

AgI Signup and view all the answers

For which salt should the aqueous solubility be most sensitive in water?

CaF2 Signup and view all the answers

The pH of a solution prepared by mixing 50.0 mL of 0.125 M KOH and 50.0 mL of 0.125 M HCl is, (blank).

7.00 Signup and view all the answers

The concentration of iodide ions in a saturated solution of silver iodide is (blank) M. The solubility product constant of AgI is 8.3x10^-17.

3.0x10^-10 Signup and view all the answers

The thermodynamic quantity that expresses the degree of disorder in a system is, (blank).

entropy Signup and view all the answers

Which of the following statements is false?

Entropy increases with the number of microstates of the system. Signup and view all the answers

The concentration of iodide ions in a saturated solution of lead (II) iodide is, (blank) M. The solubility product constant of PbI2 is 1.4x10^-8.

3.0x10^-3 Signup and view all the answers

Study Notes

Acid-Base Concepts

Weak acid identified: Hydrofluoric acid (HF) is a weak acid compared to strong acids like HCl, HBr, HNO3, and HClO4.
Weakest acid from options: Hydrocyanic acid (HCN) has the lowest acid dissociation constant (Ka = 4.9x10^-10), making it the weakest acid among the listed options.
Classification of acids: Nitrous acid (weak), Hydrochloric acid (strong), and Hydrofluoric acid (weak) classified as weak (W), strong (S) giving WWW-weak, strong, weak classification.

Equilibrium and Bases

Weak base equilibrium: A- + H2O ↔ HA + OH- corresponds to Ka equilibrium for HA.
Weak base identification: Hypochlorite ion (ClO-) acts as a weak base in water, while Cl−, NO3−, and OH− do not.
Weakest conjugate base: Fluoride ion (F-) is the weakest base among the options provided.

Strong Acids and Buffers

Strongest acid identification: Conjugate acidNH3CH3+ is considered the strongest from the given set.
Basic solution formation: Solutions containing sodium fluoride (NaF) and potassium carbonate (K2CO3) will form basic solutions, while NH4Cl and Cu(NO3)2 will not.
Neutral pH solution: A 0.1 M NaNO3 solution has a neutral pH of 7.0.

Conjugate Acids and Mixing Solutions

Conjugate acid of ammonia (NH3): Corresponds to ammonium ion (NH4+).
Buffer formation: NaCl and HCl cannot form a buffer system.
Effect of HCl addition: Adding HCl to a solution of fluoride ions and hydrogen fluoride increases H+ ion concentration, drives equilibrium towards hydrogen fluoride, and decreases fluoride ion concentration.

Buffer Solutions Preparation

Equal concentrations of weak acid and conjugate base: At this point, -log of H+ concentration equals -log of Ka, indicating equilibrium.
Hydrofluoric acid can be mixed with NaOH to create a buffer solution.
Sodium acetate can produce a buffer with either acetic acid or hydrochloric acid.

Solubility and Molarity

Greatest molar solubility: Calcium fluoride (CaF2) exhibits the greatest molar solubility compared to CdCO3, Cd(OH)2, AgI, and ZnCO3.
Smallest molar solubility: Silver iodide (AgI) has the least molar solubility among the listed compounds.
Aqueous solubility sensitivity: Calcium fluoride (CaF2) solubility is most sensitive to changes in water.

Thermodynamics and Entropy

Change of state: The change in entropy depends on the initial and final states and the path taken between them.
Entropy in spontaneous processes: Any irreversible process leads to an increase in entropy, and the universe's entropy always increases in spontaneous reactions.
Entropy correlates with microstates: More microstates equate to greater entropy within the system.

Lead Iodide Solubility

Concentration of iodide ions in saturated lead (II) iodide solution corresponds to a solubility product constant (Ksp) of 1.4x10^-8.

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Description

Test your knowledge on acid-base concepts, including classifications of acids and bases, and the characteristics of weak and strong acids. This quiz covers the fundamentals of equilibria, the identification of weak acids and bases, and the strongest acid among various options.