Q: Which statement about the autoionization of water is correct?

The product $$[H^+][OH^-] is $$always $$1.0 \times 10$$^{-14}$$ at 25°C.

Question 1

Which of the following best describes a Brønsted-Lowry acid?

Accepted Answer

A substance that donates a proton ($$H^+) in a $$chemical reaction.

Question 2

Which of the following pairs are conjugate acid-base pairs?

Accepted Answer

$$NH_3$$ and $$NH_4$$^+$$

Question 3

Given the reaction: $$NH_3 + H_2O$$ \rightarrow $$NH_4^+ + OH$$^-$$, which species acts as the Brønsted-Lowry base?

Accepted Answer

$$NH_3$$

Question 4

What is the $$pH of a $$solution with $$[H^+] = 1.0 	imes 10$$^{-4}$$ M?

Accepted Answer

$$pH = 4.0$$

Question 5

If the $$pOH of a $$solution is 3.0 at 25°C, what is the $$pH$$?

Accepted Answer

$$pH = 11.0$$

Question 6

Which of the following is a strong acid?

Accepted Answer

$$HNO_3$$

Question 7

Calculate the $$pH of a 0.01 M$$ $$HCl$$ solution.

Accepted Answer

$$pH = 2.0$$

Question 8

Which statement about the autoionization of water is correct?

Accepted Answer

The product $$[H^+][OH^-] is $$always $$1.0 	imes 10$$^{-14}$$ at 25°C.

Question 9

A solution has $$[OH^-] = 1.0 	imes 10$$^{-9}$$ M. What is its pH$?

Accepted Answer

$$pH = 5.0$$

Question 10

Which of the following is true for a weak acid in water?

Accepted Answer

It partially dissociates, and $$K_a is $$much less than 1.

Question 11

What is the conjugate base of $$HCO_3$$^-$$?

Accepted Answer

$$CO_3$$^{2-}$$

Question 12

Which indicator would be most suitable for measuring the $$pH of a $$solution expected to be around $$pH = 4.5$$?

Accepted Answer

Methyl red

Question 13

A student mixes $$0.1 M$$ $$NaOH$$ with water. What is the $$pH of $$the resulting solution?

Accepted Answer

$$pH = 13.0$$

Question 14

Which of the following equations correctly relates $$pH$$ and $$[H^+]$$?

Accepted Answer

$$pH = -\log_{10}[H^+]$$

Question 15

If $$[H^+] = [OH^-]$$, what is the $$pH of $$the solution at 25°C?

Accepted Answer

$$pH = 7.0$$

Question 16

Which of the following is a correct statement about strong bases?

Accepted Answer

Strong bases dissociate completely in water to produce $$OH^-$$ ions.

Question 17

A solution has $$pH = 8.5. $$Which of the following best describes the solution?

Accepted Answer

It is basic.

Question 18

Which of the following is the acid dissociation constant ($$K_a) $$expression for $$HA \rightleftharpoons H^+ + A^-$$?

Accepted Answer

$$K_a = \frac{[H^+][A^-]}{[HA]}$$

Question 19

A weak acid has $$K_a = 1.8 	imes 10$$^{-5}$$. If the initial concentration is 0.10$ M, which of the following best describes the $$[H^+]$$ at equilibrium?

Accepted Answer

Much less than $$0.10 M$$

Acid-Base Equilibria: Concepts, Calculations, and Applications

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