Q: Which of the following equations correctly relates the concentrations of $$[\mathrm{H}^+]$$ and $$[\mathrm{OH}^-] in $$water at 25°C?

$$[\mathrm{H}^+][\mathrm{OH}^-] = 1.0 \times 10$$^{-14}$$

Question 1

Which of the following statements best describes the relationship between pH and pOH at 25°C?

Accepted Answer

$$\mathrm{pH} + \mathrm{pOH} = 14$$

Question 2

A solution has $$[\mathrm{H}^+] = 1.0 	imes 10$$^{-4}$$\ \mathrm{M}. $$What is the pH of this solution?

Accepted Answer

$$\mathrm{pH} = 4$$

Question 3

Which of the following acids is most likely to be found in citrus fruits such as lemons and limes?

Accepted Answer

Citric acid ($$\mathrm{H_3C_6H_5O_7})$$

Question 4

Which of the following bases is commonly used as an antacid and a source of $$\mathrm{CO_2$}$$?

Accepted Answer

Sodium bicarbonate ($$\mathrm{$$NaHCO_3$$})$$

Question 5

A student prepares a buffer by mixing equal concentrations of acetic acid ($$\mathrm{HC_2H_3O_2}$$, $$pK_a = 4.8) $$and sodium acetate ($$\mathrm{NaC_2H_3O_2}). $$What is the pH of the buffer?

Accepted Answer

$$\mathrm{pH} = 4.8$$

Question 6

Which of the following equations correctly relates the concentrations of $$[\mathrm{H}^+]$$ and $$[\mathrm{OH}^-] in $$water at 25°C?

Accepted Answer

$$[\mathrm{H}^+][\mathrm{OH}^-] = 1.0 	imes 10$$^{-14}$$

Question 7

Which of the following best explains why $$\mathrm{HCl} is a $$strong acid while $$\mathrm{CH_4$} is $$not acidic?

Accepted Answer

$$\mathrm{HCl}$$ has a highly polar H-Cl bond and $$\mathrm{CH_4$}$$ does not.

Question 8

A solution is prepared by mixing 100 mL of 0.30 M $$\mathrm{$$HNO_2$$}$$ and 100 mL of 0.30 M $$\mathrm{$$KNO_2$$}. $$What happens to the pH if a few drops of 1.0 M $$\mathrm{HCl}$$ are added?

Accepted Answer

The pH changes only slightly because the added $$\mathrm{H^+} is $$neutralized by $$\mathrm{NO_2$^-}.$$

Question 9

Which of the following is the correct net ionic equation for the neutralization of a strong acid with a strong base?

Accepted Answer

$$\mathrm{H^+ (aq) + OH^- (aq) \rightarrow H_2O (l)}$$

Question 10

A titration curve for a polyprotic acid shows three distinct equivalence points. What does this indicate about the acid?

Accepted Answer

The acid can donate three protons.

Question 11

Which of the following best describes the effect of increasing the concentration of both components of a buffer while keeping their ratio constant?

Accepted Answer

The buffer capacity increases but the pH remains the same.

Question 12

A solution of $$0.05\ \mathrm{M}$$ $$\mathrm{NaOH}$$ has a pOH of 1.30. What is the pH of this solution at 25°C?

Accepted Answer

$$\mathrm{pH} = 12.70$$

Question 13

Which of the following pairs will create a buffer with a pH closest to 7.5 when mixed in equimolar amounts?

Accepted Answer

$$\mathrm{HClO}$$ and $$\mathrm{ClO^-}$$

Question 14

Which of the following best describes the color change of phenolphthalein in a titration?

Accepted Answer

It changes from colorless to pink.

Question 15

A buffer solution is made by mixing acetic acid and sodium acetate. If a small amount of NaOH is added, what happens?

Accepted Answer

The pH changes only slightly because the acetic acid neutralizes the added base.

Question 16

Which of the following is the correct Henderson-Hasselbalch equation for a buffer made from a weak acid and its conjugate base?

Accepted Answer

$$\mathrm{pH} = \mathrm{p}K_a + \log \left( \frac{[	ext{base}]}{[	ext{acid}]} ight)$$

Question 17

Which of the following acids has the lowest $$K_a$$ value based on the table provided?

Accepted Answer

$$\mathrm{HOC_6H_5}$$

Question 18

If the pH of a solution is less than the pKa of an acid, which form predominates?

Accepted Answer

The acid form ($$\mathrm{HA})$$

Acids, Bases, and Aqueous Equilibria: Study Notes for General Chemistry

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