Chapter 6 Multiple Choice Questions

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. Which ONE of the following is the best description of a protogenic solvent?

A protogenic solvent accepts electron lone pairs correct incorrect

A protogenic solvent neither accepts or donates protons correct incorrect

A protogenic solvent donates protons correct incorrect

A protogenic solvent donates or accepts electron lone pairs correct incorrect

A protogenic solvent accepts protons correct incorrect

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. For an aqueous solution of hydrochloric acid (HCl) the pH was found to be 4.18 units. What is the concentration of HCl in this solution?

2.2 x10^-3 M correct incorrect

1.4 x 10^-3 M correct incorrect

3.2 x 10^-4 M correct incorrect

4.8 x 10^-4 M correct incorrect

6.6 x 10^-5 M correct incorrect

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. What is the pH of a 0.015 M solution of potassium hydroxide (KOH)?

1.8 correct incorrect

12.2 correct incorrect

5.6 correct incorrect

8.8 correct incorrect

13.1 correct incorrect

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. A solution of the weakly basic drug erythromycin (pKb = 5.2) is buffered to pH 7.4.
What percentage of the drug will be ionised at this pH?

25% correct incorrect

72% correct incorrect

75% correct incorrect

96% correct incorrect

99% correct incorrect

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. A solution of diclofenac (pK_a = 4.15) is buffered to pH 5.5. How much diclofenac will be ionised at this pH?

100% correct incorrect

96% correct incorrect

50% correct incorrect

22% correct incorrect

1% correct incorrect

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. A buffer solution contains 0.36 M sodium acetate (CH₃COONa) and 0.45 M acetic acid (CH₃COOH), pK_a = 4.8. What is the pH of this buffer solution?

4.7 correct incorrect

5.2 correct incorrect

3.8 correct incorrect

6.1 correct incorrect

6.9 correct incorrect

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. 250 mL of a buffer contains 0.05 mol acetic acid (CH₃COOH) and 0.03 mol sodium acetate (CH₃COONa). What is the maximum buffer capacity of this buffer?

0.46 mol L^-1 pH unit^-1 correct incorrect

0.18 mol L^-1 pH unit^-1 correct incorrect

0.22 mol L^-1 pH unit^-1 correct incorrect

1.84 mol L^-1 pH unit^-1 correct incorrect

3.24 mol L^-1 pH unit^-1 correct incorrect

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. What is the isoelectric point for phenylalanine given the pK_a for the COOH group is 1.83 and the NH₃⁺ group is 9.13?

2.43 correct incorrect

4.83 correct incorrect

5.48 correct incorrect

9.13 correct incorrect

10.96 correct incorrect

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. Which one of the following statements is true?

A strong electrolyte solution is a solution that always contains a high concentration of an acid or base. correct incorrect

The strength of an acid can be influenced by the solvent into which it is placed correct incorrect

In aqueous solution a strong acid will dissociate to form a strong conjugate base and together these form a conjugate pair. correct incorrect

pH 7 is considered to be neutral pH at all temperatures correct incorrect

A buffer solution has a fixed pH value that does change at all upon the addition of acid or base. correct incorrect

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. Which one of the following statements concerning active pharmaceutical ingredients (APIs) is false?

The degree of ionisation of an API is dependent upon its pK_a or pK_b. correct incorrect

The degree of ionisation of an API is dependent upon the pH of the surrounding solution. correct incorrect

The extent to which an API may be absorbed is influenced by the extent of its ionisation correct incorrect

APIs pass through biological membranes more readily when they are ionised correct incorrect

Temperature can affect the degree of ionisation of APIs correct incorrect