Question 1

What statement is most consistent for an acid with a pH = 1?

Accepted Answer

A) one one-hundredth as strong as an acid with a pH of 3 
B) half a strong as an acid with a pH = 3 
C) twice as strong as an acid with a pH of 3 
D) one hundred times as strong as an acid with a pH = 3 
A) one one-hundredth as strong as an acid with a pH of 3 
B) half a strong as an acid with a pH = 3 
C) twice as strong as an acid with a pH of 3 
D) one hundred times as strong as an acid with a pH = 3

Question 2

Vinegar is a 5.0% solution by weight of acetic acid (CH3CO2H)in water.Given that the pH for acetic acid is 2.41,the Ka = 1.8 × 10-5 and assuming the density of vinegar to be 1.00 g/cm3,what is the percent dissociation of acetic acid in vinegar?

Accepted Answer

A) 0.47% 
B) 1.5% 
C) 4.0% 
D) 5.0% 
A) 0.47% 
B) 1.5% 
C) 4.0% 
D) 5.0%

Question 3

Calculate the pH of a 0.20 M H2SO3,solution that has the stepwise dissociation constants Ka1 = 1.5 × 10-2 and Ka2 = 6.3 × 10-8.

Accepted Answer

A) 1.26 
B) 1.32 
C) 1.82 
D) 2.52 
A) 1.26 
B) 1.32 
C) 1.82 
D) 2.52

Question 4

Which of the following Br∅nsted-Lowry acids does not behave as a strong acid when it is dissolved in water?

Accepted Answer

A) HBr 
B) HCl 
C) HNO2 
D) HClO4 
A) HBr 
B) HCl 
C) HNO2 
D) HClO4

Question 5

The following pictures represent equal volumes of aqueous solutions of three acids HA (A = X,Y,or Z);water molecules have been omitted for clarity.  
-Arrange the conjugate bases (A- = X-,Y-,or Z-)in order of increasing value of Kb.

Accepted Answer

A) Kb(Z-)b(Y-)b(X-) 
B) Kb(Y-)b(Z-)b(X-) 
C) Kb(Z-)b(X-)b(Y-) 
D) Kb(X-)b(Z-)b(Y-) 
A) Kb(Z-)b(Y-)b(X-) 
B) Kb(Y-)b(Z-)b(X-) 
C) Kb(Z-)b(X-)b(Y-) 
D) Kb(X-)b(Z-)b(Y-)

Question 6

-Which of the above pictures represents a solution of a weak diprotic acid H2A for which Ka1 >> Ka2? (Water molecules have been omitted for clarity. )

Accepted Answer

A) picture (a) 
B) picture (b) 
C) picture (c) 
D) picture (d) 
A) picture (a) 
B) picture (b) 
C) picture (c) 
D) picture (d)

Question 7

What is the relationship between Ka and Kb at 25°C for a conjugate acid base pair?

Accepted Answer

A) Ka × Kb = 1 × 10-14 
B) Ka/Kb = 1 × 10-14 
C) Kb/Ka = 1 × 10-14 
D) Ka - Kb = 1 × 10-14 
A) Ka × Kb = 1 × 10-14 
B) Ka/Kb = 1 × 10-14 
C) Kb/Ka = 1 × 10-14 
D) Ka - Kb = 1 × 10-14

Question 8

Para-Aminobenzoic acid (PABA),p-H2NC6H4(COOH),is used in some sunscreens and hair conditioning products.Calculate the pH of an aqueous solution with [PABA] = 0.030 M and Ka = 2.2 × 10-5.

Accepted Answer

A) 1.52 
B) 3.09 
C) 4.66 
D) 6.18 
A) 1.52 
B) 3.09 
C) 4.66 
D) 6.18

Question 9

What is the second stepwise equilibrium constant expression for phosphoric acid H3PO4?

Accepted Answer

A) Ka2 = ([H3O+][H2PO4-])/([H3PO4]) 
B) Ka2 = ([H3O+]2[HPO42-])/([H3PO4]) 
C) Ka2 = ([H3O+]3[PO43-])/([H3PO4]) 
D) Ka2 = ([H3O+][HPO42-])/([H2PO4-]) 
A) Ka2 = ([H3O+][H2PO4-])/([H3PO4]) 
B) Ka2 = ([H3O+]2[HPO42-])/([H3PO4]) 
C) Ka2 = ([H3O+]3[PO43-])/([H3PO4]) 
D) Ka2 = ([H3O+][HPO42-])/([H2PO4-])

Question 10

In the following reaction the unshaded spheres represent H atoms.  
-Identify the Br∅nsted-Lowry acids.

Accepted Answer

A) (1)and (3) 
B) (1)and (4) 
C) (2)and (3) 
D) (2)and (4) 
A) (1)and (3) 
B) (1)and (4) 
C) (2)and (3) 
D) (2)and (4)

Question 11

What is the pH of a solution prepared by diluting 25.00 mL of 0.020 M Ba(OH)2 with enough water to produce a total volume of 250.00 mL?

Accepted Answer

A) 2.40 
B) 2.70 
C) 11.30 
D) 11.60 
A) 2.40 
B) 2.70 
C) 11.30 
D) 11.60

Question 12

What is the pH of a solution prepared by mixing 100.00 mL of 0.20 M HCl with 50.00 mL of 0.30 M HCl? Assume that the volumes are additive.

Accepted Answer

A) 0.25 
B) 0.30 
C) 0.63 
D) 1.70 
A) 0.25 
B) 0.30 
C) 0.63 
D) 1.70

Question 13

What is the hydroxide ion concentration of a lye solution that has a pH of 11.20?

Accepted Answer

A) 6.31 × 10-12 M 
B) 1.58 × 10-3 M 
C) 2.80 M 
D) 11.20 M 
A) 6.31 × 10-12 M 
B) 1.58 × 10-3 M 
C) 2.80 M 
D) 11.20 M

Question 14

Bromothymol blue indicator changes color from yellow at a pH of 6.0 to blue at a pH of 7.6.Methyl red indicator changes color from red at a pH of 4.4 to yellow at a pH of 6.2.A sample of saliva having [H3O+] = 6.310 × 10-7 would impart a ________ color to bromothymol blue and a ________ color to methyl red.

Accepted Answer

Question 15

What is the hydroxide ion concentration and the pH for a hydrochloric acid solution that has a hydronium ion concentration of

Accepted Answer

A) 6.67 × 10-8 M,6.82 
B) 6.67 × 10-8 M,7.18 
C) 6.67 × 10-9 M,5.82 
D) 6.67 × 10-9 M,8.17 
A) 6.67 × 10-8 M,6.82 
B) 6.67 × 10-8 M,7.18 
C) 6.67 × 10-9 M,5.82 
D) 6.67 × 10-9 M,8.17

Question 16

What is the equilibrium constant expression (Ka)for the acid dissociation of hydrocyanic acid HCN? The equation of interest is HCN(aq)+ H2O(l)⇌ H3O+(aq)+ CN-(aq).

Accepted Answer

A) Ka = ([H3O+][CN-])/([HCN][H2O]) 
B) Ka = ([H3O+][CN-])/([HCN]) 
C) Ka = ([HCN][H2O])/([H3O+][CN-]) 
D) Ka = ([HCN])/([H3O+][CN-]) 
A) Ka = ([H3O+][CN-])/([HCN][H2O]) 
B) Ka = ([H3O+][CN-])/([HCN]) 
C) Ka = ([HCN][H2O])/([H3O+][CN-]) 
D) Ka = ([HCN])/([H3O+][CN-])

Question 17

What is the hydronium ion concentration and the pH for an aqueous solution of NH3 that has a hydroxide ion concentration of 2.25 × 10-3 M?

Accepted Answer

A) 4.44 × 10-11 M,3.65 
B) 4.44 × 10-11 M,10.35 
C) 4.44 × 10-12 M,2.65 
D) 4.44 × 10-12 M,11.35 
A) 4.44 × 10-11 M,3.65 
B) 4.44 × 10-11 M,10.35 
C) 4.44 × 10-12 M,2.65 
D) 4.44 × 10-12 M,11.35

Question 18

What is the weakest acid among the following?

Accepted Answer

A) SiH4 
B) PH3 
C) H2S 
D) HCl 
A) SiH4 
B) PH3 
C) H2S 
D) HCl

Question 19

Calculate the pH for an aqueous solution of acetic acid that contains 2.15 × 10-3 M hydronium ion.

Accepted Answer

A) 4.65 × 10-12 
B) 2.15 × 10-3 
C) 2.67 
D) 11.33 
A) 4.65 × 10-12 
B) 2.15 × 10-3 
C) 2.67 
D) 11.33

Question 20

The following pictures represent solutions of three salts MA;water molecules have been omitted for clarity.Dotted spheres represent AS1U1P1yS1S1P0S1U1P1-S1S1P0 ions;gray spheres represent MS1U1P1x+S1S1P0 ions;black spheres represent oxygen atoms;and unshaded spheres represent hydrogen atoms.  
-Which picture represents an acidic salt?

Accepted Answer

A) (1) 
B) (2) 
C) (3) 
D) None of these 
A) (1) 
B) (2) 
C) (3) 
D) None of these

Exam 15: Aqueous Equilibria: Acids and Bases

What statement is most consistent for an acid with a pH = 1?

Vinegar is a 5.0% solution by weight of acetic acid (CH3CO2H)in water.Given that the pH for acetic acid is 2.41,the Ka = 1.8 × 10-5 and assuming the density of vinegar to be 1.00 g/cm3,what is the percent dissociation of acetic acid in vinegar?

Calculate the pH of a 0.20 M H2SO3,solution that has the stepwise dissociation constants Ka1 = 1.5 × 10-2 and Ka2 = 6.3 × 10-8.

Which of the following Br∅nsted-Lowry acids does not behave as a strong acid when it is dissolved in water?

The following pictures represent equal volumes of aqueous solutions of three acids HA (A = X,Y,or Z);water molecules have been omitted for clarity. -Arrange the conjugate bases (A- = X-,Y-,or Z-)in order of increasing value of Kb.

-Which of the above pictures represents a solution of a weak diprotic acid H2A for which Ka1 >> Ka2? (Water molecules have been omitted for clarity. )

What is the relationship between Ka and Kb at 25°C for a conjugate acid base pair?

Para-Aminobenzoic acid (PABA),p-H2NC6H4(COOH),is used in some sunscreens and hair conditioning products.Calculate the pH of an aqueous solution with [PABA] = 0.030 M and Ka = 2.2 × 10-5.

What is the second stepwise equilibrium constant expression for phosphoric acid H3PO4?

In the following reaction the unshaded spheres represent H atoms. -Identify the Br∅nsted-Lowry acids.

What is the pH of a solution prepared by diluting 25.00 mL of 0.020 M Ba(OH)2 with enough water to produce a total volume of 250.00 mL?

What is the pH of a solution prepared by mixing 100.00 mL of 0.20 M HCl with 50.00 mL of 0.30 M HCl? Assume that the volumes are additive.

What is the hydroxide ion concentration of a lye solution that has a pH of 11.20?

What is the hydroxide ion concentration and the pH for a hydrochloric acid solution that has a hydronium ion concentration of

What is the equilibrium constant expression (Ka)for the acid dissociation of hydrocyanic acid HCN? The equation of interest is HCN(aq)+ H2O(l)⇌ H3O+(aq)+ CN-(aq).

What is the hydronium ion concentration and the pH for an aqueous solution of NH3 that has a hydroxide ion concentration of 2.25 × 10-3 M?

What is the weakest acid among the following?

Calculate the pH for an aqueous solution of acetic acid that contains 2.15 × 10-3 M hydronium ion.

The following pictures represent solutions of three salts MA;water molecules have been omitted for clarity.Dotted spheres represent Ay- ions;gray spheres represent Mx+ ions;black spheres represent oxygen atoms;and unshaded spheres represent hydrogen atoms. -Which picture represents an acidic salt?

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Periodicity and the Electronic Structure of Atoms

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Covalent Compounds: Bonding Theories and Molecular Structure

Thermochemistry: Chemical Energy

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Applications of Aqueous Equilibria

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Vinegar is a 5.0% solution by weight of acetic acid (CH₃CO₂H)in water.Given that the pH for acetic acid is 2.41,the K_a = 1.8 × 10^-5and assuming the density of vinegar to be 1.00 g/cm³,what is the percent dissociation of acetic acid in vinegar?

Calculate the pH of a 0.20 M H₂SO₃,solution that has the stepwise dissociation constants K_a1 = 1.5 × 10^-2 and K_a2 = 6.3 × 10^-8.

The following pictures represent equal volumes of aqueous solutions of three acids HA (A = X,Y,or Z);water molecules have been omitted for clarity. -Arrange the conjugate bases (A^- = X^-,Y^-,or Z^-)in order of increasing value of K_b.

-Which of the above pictures represents a solution of a weak diprotic acid H₂A for which K_a1 >> K_a2? (Water molecules have been omitted for clarity. )

What is the relationship between K_a and K_b at 25°C for a conjugate acid base pair?

Para-Aminobenzoic acid (PABA),p-H₂NC₆H₄(COOH),is used in some sunscreens and hair conditioning products.Calculate the pH of an aqueous solution with [PABA] = 0.030 M and K_a = 2.2 × 10^-5.

What is the second stepwise equilibrium constant expression for phosphoric acid H₃PO₄?

What is the pH of a solution prepared by diluting 25.00 mL of 0.020 M Ba(OH)₂ with enough water to produce a total volume of 250.00 mL?

What is the equilibrium constant expression (K_a)for the acid dissociation of hydrocyanic acid HCN? The equation of interest is HCN(aq)+ H₂O(l)⇌ H₃O⁺(aq)+ CN^-(aq).

What is the hydronium ion concentration and the pH for an aqueous solution of NH₃ that has a hydroxide ion concentration of 2.25 × 10^-3 M?

Calculate the pH for an aqueous solution of acetic acid that contains 2.15 × 10^-3 M hydronium ion.