Question 1

What species are formed in the hydrolysis reaction of NH ₄Cl with water?
NH ₄Cl + H₂ O  ??

Accepted Answer

The hydrolysis reaction of NH4Cl with water produces NH4+ and Cl- ions. The NH4+ ion can react with water to form NH3 and H3O+ ions:

NH4+ + H2O -> NH3 + H3O+

The Cl- ion does not react with water, so it remains as Cl- in the solution. Therefore, the species formed in the hydrolysis reaction are NH4+, NH3, H3O+, and Cl-.

Option C is the best choice because it includes all of these species in the correct stoichiometric ratios. Option A includes NS1U1B12S1U1B0 and HS1U1B12S1U1B0, which are not valid chemical species, and Option B includes OHS1U1P1-S1S1P0, which should be written as OH- and H2O. Option D includes NHS1U1B15S1U1B0S1U1P12, which is not a valid chemical species, and Option E includes ClOH, which is not expected to form in this reaction.

Question 2

Consider adding NaClO₄ to a basic solution. Which statement below is true?

Accepted Answer

NaClO₄ is a neutral salt because it is derived from a strong acid (HClO₄) and a strong base (NaOH), so it does not affect the pH of the solution.

Question 3

K _b for ammonia is 1.8×10^{- 5}. Calculate K _a for the ammonium ion.

Accepted Answer

The relationship between Kb and Ka for a conjugate acid-base pair is given by Ka * Kb = Kw, where Kw is the ion-product constant of water (1.0×10^-14 at 25°C). Solving for Ka gives Ka = Kw / Kb = 1.0×10^-14 / 1.8×10^-5 = 5.6×10^-10.

Question 4

Employing a neutralization reaction , which reactants are used to prepare the salt Sodium cyanide, NaCN? reactants?
→NaCN

Accepted Answer

Sodium cyanide (NaCN) can be prepared by reacting sodium hydroxide (NaOH) with hydrogen cyanide (HCN) in a neutralization reaction, where the hydroxide ion (OH-) from NaOH reacts with the hydrogen ion (H+) from HCN to form water, leaving NaCN as the salt product.

Question 5

A water soluble salt composed of the anion of a weak acid and the cation of a strong base is dissolved in pure water. The resulting solution:

Accepted Answer

The anion of a weak acid is a weak base and will hydrolyze in water, creating OH- ions. Since the cation of a strong base has no acidic properties, the resulting solution will have a higher concentration of OH- ions than H+ ions, making it basic with a pH greater than 7.

Question 6

Employing a neutralization reaction , which reactants are required to prepare the salt Barium acetate, Ba(CH₃COO)₂ reactants? →Ba(CH₃COO)₂

Accepted Answer

Barium acetate is a salt formed by the reaction between a base (Ba(OH)2) and an acid (CH3COOH). Therefore, the best option is D, which contains Ba(OH)2 and CH3COOH as reactants.

Question 7

Consider the salt pyridinium acetate, [(C₅H₅NH⁺)(C₂H₃O₂^{1 -})], That is derived from a combination of a weak acid , HC₂H₃O₂, and a weak base , C₅H₅N, As shown below. C₅H₅N + HC₂H₃O₂→[(C₅H₅NH⁺)(C₂H₃O₂^{1 -})] K _b(C₅H₅N) = 1.7×10^{- 9} and K _a(HC₂H₃O₂) = 1.8×10^{- 5} Which statement listed below is true?

Accepted Answer

The salt is derived from a weak base (pyridine, with Kb = 1.7×10^-9) and a weak acid (acetic acid, with Ka = 1.8×10^-5). Since the acid is stronger than the base (as indicated by a larger Ka value compared to Kb), the resulting solution of the salt in water will be acidic.

Question 8

If we compare the acid/base properties of a 0.5 M solution of A^- to a 0.5 M solution of HA, K _a = 1.0×10^{- 4}:

Accepted Answer

A⁻ is the conjugate base of the weak acid HA. In solution, A⁻ will react with water to form OH⁻, making the solution basic.

Question 9

What is the base ionization constant , K _b, for iodate, IO₃^{1 -}, if the acid ionization constant of HIO₃ equals 1.6×10^{- 1}?

Accepted Answer

The base ionization constant for iodate can be determined using the acid ionization constant of HIO3 and the equilibrium equation:
HIO3 + H2O ⇌ H3O+ + IO3-
The equilibrium constant for this reaction is the acid ionization constant:
Ka = [H3O+][IO3-]/[HIO3]
Since the base ionization constant is the inverse of the acid ionization constant (Kb = Kw/Ka), we can use this equation to solve for Kb:
Kb = Kw/Ka = (1.0 × 10^-14)/(1.6 × 10^-1^5) = 6.3 × 10^-14
Therefore, the best choice is B.

Question 10

Employing a neutralization reaction , what reactants are required to prepare the salt, KNO₃ reactants? →KNO₃

Accepted Answer

To prepare the salt KNO₃, we need to neutralize an acid with a base. The symbol for the cation potassium is K+, and the anion nitrate is NO3-. Thus, we can deduce that the acid needed to prepare KNO₃ is HNO3. The base needed to neutralize the acid is KOH, making the reactants KOH and HNO3, which results in the salt KNO₃ and water (H2O) as byproducts. So, the correct answer is D) KOH and HNO₃.

Question 11

When 20.0 grams of a water soluble salt dissolves in 1.0 L of pure water the pH was found to be less than seven. Which of the following statements about the salt is most probable?

Accepted Answer

When a salt dissolves in water and the solution becomes acidic (pH less than 7), it indicates that the salt is releasing hydrogen ions (H+) into the solution. This typically happens when the salt contains the conjugate acid of a weak base. A weak base does not fully ionize in water, and its conjugate acid can release H+ ions, making the solution acidic.

Question 12

Which of the following solutions will not be basic?

Accepted Answer

Solution C will not be basic because the chloride of the conjugate acid of a weak base typically forms a solution that is either neutral or slightly acidic, depending on the strength of the conjugate acid.

Question 13

What is the acid ionization constant , K _a, for lactic acid, CH₃CH(OH)COOH, if the base ionization constant, K _b, of CH₃CH(OH)COO^- equals 7.1×10^{- 11}?

Accepted Answer

The relationship between the acid ionization constant (Ka) and the base ionization constant (Kb) for a conjugate acid-base pair is given by the equation Ka * Kb = Kw, where Kw is the ionization constant of water at 25°C, equal to 1.0 × 10^-14. Given Kb = 7.1 × 10^-11 for the conjugate base of lactic acid, solving for Ka gives Ka = Kw / Kb = (1.0 × 10^-14) / (7.1 × 10^-11) = 1.4 × 10^-4.

Question 14

Employing a neutralization reaction , which reactants are used to prepare the salt Potassium Sulfate, K₂SO₄ reactants? →K₂SO₄

Accepted Answer

Potassium sulfate can be prepared by neutralizing sulfuric acid (HSO4-) with potassium hydroxide (KOH). The reaction is: HSO4- + KOH → KSO4 + H2O

Question 15

K _a for HF is 3.5×10^{- 4}. Calculate K _b for the fluoride ion.

Accepted Answer

The equilibrium constant for the reaction HF ⇌ H+ + F- is given. To find the equilibrium constant for the reverse reaction, we need to invert the expression for K: K = [H+][F-]/[HF]. This will give us the equilibrium constant for the reaction F- + H+ ⇌ HF. The stoichiometry of the reaction has not changed, so the values of Kc and Kp will remain the same. The value of K for the reverse reaction will be the inverse of K for the forward reaction, which means K for F- will be the inverse of K for HF. Therefore, the correct answer is E, which is the inverse of the given value of K for HF.

Question 16

K _a for HF is 3.5×10^{- 4}. A 0.10 M solution of sodium fluoride is:

Accepted Answer

The equation given is K= [H+][F-]/[HF]. Since NaF is a salt of a strong base and weak acid, it will hydrolyze in water, producing OH- ions. This will shift the equilibrium to the left, creating more HF and H+ ions, making the solution weakly acidic. Therefore, the correct answer is option D, weakly basic, which is the opposite of weakly acidic, and it is incorrect to choose any other option.

Question 17

What species are formed in the hydrolysis reaction of KCN with water?
KCN + H₂ O  ??

Accepted Answer

In the hydrolysis reaction of KCN with water, the cyanide ion (CN-) reacts with a water molecule to form hydronium ion (H3O+) and hydrocyanic acid (HCN), as shown in the following equation: KCN + H2O → HCN + KOH. Therefore, option B represents the correct species formed in the reaction. Option A, C, D, and E are incorrect because they do not represent the correct products of the reaction.

Question 18

Which of these aqueous solutions would have a pH greater than 7?

Accepted Answer

Sodium acetate is a salt of a weak acid (acetic acid) and a strong base (sodium hydroxide) and when dissolved in water it undergoes hydrolysis releasing hydroxide ions, which makes the solution basic with a pH greater than 7.

Question 19

What species are formed in the hydrolysis of KF with water ?
KF + H₂ O  ??

Accepted Answer

When KF is hydrolyzed with water, it forms HF (hydrofluoric acid) and KOH (potassium hydroxide), according to the following reaction:

KF + H₂O → HF + KOH

Therefore, the correct choice is E.

Question 20

What is the base ionization constant , K _b, for ClO₂^{1 -} if the acid ionization constant, K _a, of HClO₂ equals 1.1×10^{- 2}?

Accepted Answer

The relationship between the acid ionization constant (Ka) and the base ionization constant (Kb) for a conjugate acid-base pair is given by the equation Ka * Kb = Kw, where Kw is the ion-product constant of water (1.0×10^-14 at 25°C). Solving for Kb gives Kb = Kw / Ka = 1.0×10^-14 / 1.1×10^-2 = 9.1×10^-13.

Quiz 15: Solutions of Acids and Bases

What species are formed in the hydrolysis reaction of NH ₄Cl with water? NH ₄Cl + H₂ O ??

Consider adding NaClO₄ to a basic solution. Which statement below is true?

K _b for ammonia is 1.8×10^{- 5}. Calculate K _a for the ammonium ion.

Employing a neutralization reaction , which reactants are used to prepare the salt Sodium cyanide, NaCN? reactants? →NaCN

A water soluble salt composed of the anion of a weak acid and the cation of a strong base is dissolved in pure water. The resulting solution:

Employing a neutralization reaction , which reactants are required to prepare the salt Barium acetate, Ba(CH₃COO) ₂ reactants? →Ba(CH₃COO) ₂

If we compare the acid/base properties of a 0.5 M solution of A^- to a 0.5 M solution of HA, K _a = 1.0×10^{- 4}:

What is the base ionization constant , K _b, for iodate, IO₃^{1 -}, if the acid ionization constant of HIO₃ equals 1.6×10^{- 1}?

Employing a neutralization reaction , what reactants are required to prepare the salt, KNO₃ reactants? →KNO₃

When 20.0 grams of a water soluble salt dissolves in 1.0 L of pure water the pH was found to be less than seven. Which of the following statements about the salt is most probable?

Which of the following solutions will not be basic?

What is the acid ionization constant , K _a, for lactic acid, CH₃CH(OH) COOH, if the base ionization constant, K _b, of CH₃CH(OH) COO^- equals 7.1×10^{- 11}?

Employing a neutralization reaction , which reactants are used to prepare the salt Potassium Sulfate, K₂SO₄ reactants? →K₂SO₄

K _a for HF is 3.5×10^{- 4}. Calculate K _b for the fluoride ion.

K _a for HF is 3.5×10^{- 4}. A 0.10 M solution of sodium fluoride is:

What species are formed in the hydrolysis reaction of KCN with water? KCN + H₂ O ??

Which of these aqueous solutions would have a pH greater than 7?

What species are formed in the hydrolysis of KF with water ? KF + H₂ O ??

What is the base ionization constant , K _b, for ClO₂^{1 -} if the acid ionization constant, K _a, of HClO₂ equals 1.1×10^{- 2}?

Quiz 15: Solutions of Acids and Bases

What species are formed in the hydrolysis reaction of NH ₄Cl with water? NH ₄Cl + H₂ O ??

Consider adding NaClO4 to a basic solution. Which statement below is true?

K b for ammonia is 1.8×10 - 5. Calculate K a for the ammonium ion.

Employing a neutralization reaction , which reactants are used to prepare the salt Sodium cyanide, NaCN? reactants? →NaCN

A water soluble salt composed of the anion of a weak acid and the cation of a strong base is dissolved in pure water. The resulting solution:

Employing a neutralization reaction , which reactants are required to prepare the salt Barium acetate, Ba(CH3COO) 2 reactants? →Ba(CH3COO) 2

If we compare the acid/base properties of a 0.5 M solution of A - to a 0.5 M solution of HA, K a = 1.0×10 - 4:

What is the base ionization constant , K b, for iodate, IO31 - , if the acid ionization constant of HIO3 equals 1.6×10 - 1?

Employing a neutralization reaction , what reactants are required to prepare the salt, KNO3 reactants? →KNO3

When 20.0 grams of a water soluble salt dissolves in 1.0 L of pure water the pH was found to be less than seven. Which of the following statements about the salt is most probable?

Which of the following solutions will not be basic?

What is the acid ionization constant , K a, for lactic acid, CH3CH(OH) COOH, if the base ionization constant, K b, of CH3CH(OH) COO - equals 7.1×10 - 11?

Employing a neutralization reaction , which reactants are used to prepare the salt Potassium Sulfate, K2SO4 reactants? →K2SO4

K a for HF is 3.5×10 - 4. Calculate K b for the fluoride ion.

K a for HF is 3.5×10 - 4. A 0.10 M solution of sodium fluoride is:

What species are formed in the hydrolysis reaction of KCN with water? KCN + H₂ O ??

Which of these aqueous solutions would have a pH greater than 7?

What species are formed in the hydrolysis of KF with water ? KF + H₂ O ??

What is the base ionization constant , K b, for ClO21 - if the acid ionization constant, K a, of HClO2 equals 1.1×10 - 2?

Consider adding NaClO₄ to a basic solution. Which statement below is true?

K _b for ammonia is 1.8×10^{- 5}. Calculate K _a for the ammonium ion.

Employing a neutralization reaction , which reactants are required to prepare the salt Barium acetate, Ba(CH₃COO) ₂ reactants? →Ba(CH₃COO) ₂

If we compare the acid/base properties of a 0.5 M solution of A^- to a 0.5 M solution of HA, K _a = 1.0×10^{- 4}:

What is the base ionization constant , K _b, for iodate, IO₃^{1 -}, if the acid ionization constant of HIO₃ equals 1.6×10^{- 1}?

Employing a neutralization reaction , what reactants are required to prepare the salt, KNO₃ reactants? →KNO₃

What is the acid ionization constant , K _a, for lactic acid, CH₃CH(OH) COOH, if the base ionization constant, K _b, of CH₃CH(OH) COO^- equals 7.1×10^{- 11}?

Employing a neutralization reaction , which reactants are used to prepare the salt Potassium Sulfate, K₂SO₄ reactants? →K₂SO₄

K _a for HF is 3.5×10^{- 4}. Calculate K _b for the fluoride ion.

K _a for HF is 3.5×10^{- 4}. A 0.10 M solution of sodium fluoride is:

What is the base ionization constant , K _b, for ClO₂^{1 -} if the acid ionization constant, K _a, of HClO₂ equals 1.1×10^{- 2}?