Q: Which acid is the strongest? (Compare $$K_a$$ values.)

$$HSO_4$$^-$$, K_a = 1.2 \times 10$$^{-2}$

Question 1

Which of the following pairs of compounds will form a solution based on the principle 'like dissolves like'?

Accepted Answer

Benzene (C6H6) and hexane (C6H14)

Question 2

According to the solubility rules, which ionic compound is soluble in water?

Accepted Answer

Ca(NO3)2

Question 3

Which of the following will increase the solubility of NaCl in water?

Accepted Answer

Increasing temperature

Question 4

A solution is made by dissolving 3.88 g of NaCl in enough water to make 67.8 mL of solution. What is the concentration of sodium chloride in weight/volume percent ($$w/v$$%)?

$$	ext{(w/v)%} = \frac{	ext{mass of solute (g)}}{	ext{volume of solution (mL)}} 	imes 100$$

Accepted Answer

5.72

Question 5

A sample of seawater contains 1.3 g of Ca$$^{2+}$$ ions in 3100 kg of solution. What is the Ca$$^{2+}$$ ion concentration of this solution in ppm?

$$	ext{ppm} = \frac{	ext{mass of solute (g)}}{	ext{mass of solution (g)}} 	imes 10^6$

Accepted Answer

420

Question 6

What is the molarity of a solution made by dissolving 36.29 g of NaCl (molar mass = 58.44 g/mol) in 2.30 L of solution?

$$	ext{Molarity} = \frac{	ext{moles of solute}}{	ext{volume of solution (L)}}$$

Accepted Answer

0.270 M

Question 7

A lab technician creates a 0.700 M solution that is too concentrated. What volume of water must be added to create a 15 mL solution with a concentration of 0.140 M?

$$M_1V_1 = M_2V_2$$

Accepted Answer

12 mL

Question 8

Which solution composition has the highest freezing point?

(Assume all are KCl in water; freezing point depression depends on total solute particles per kg solvent.)

Accepted Answer

0.25 mol KCl in 1.00 kg water

Question 9

Compared to pure water, a 1.0 M sucrose solution would have a _____ boiling point and a _____ vapor pressure.

Accepted Answer

Higher; lower

Question 10

A hypotonic solution has ________ osmotic pressure than/as body fluids.

Accepted Answer

A lower

Question 11

Which species can act as a Brønsted acid?

Accepted Answer

HCl

Question 12

Which species is a diprotic acid?

Accepted Answer

H$$_2CO$_3$$

Question 13

What is the conjugate acid of HS$$^-$$?

Accepted Answer

H$$_2S$$

Question 14

What is the correct name of HNO$$_2$$?

Accepted Answer

Nitrous acid

Question 15

Identify the missing product in the reaction:

$$NH_3 + $$HCl \rightleftharpoons $$NH_4$$^+ + \underline{\hspace{1cm}}$$

Accepted Answer

Cl$$^-$$

Question 16

Which acid is the strongest?

(Compare $$K_a$$ values.)

Accepted Answer

$$HSO_4$$^-$$, K_a = 1.2 	imes 10$$^{-2}$

Question 17

The $$[H_3O^+] in a $$cabernet sauvignon is $$5.9 	imes 10$$^{-4}$$ M. What is $$[OH^-]$$ in this liquor?

K_w$$ = [H_3O^+][OH^-] = 1.0 	imes $$10^{-14}$$

Accepted Answer

1.7 	imes $$10^{-11} M$$

Question 18

Which pH value indicates the highest $$[OH^-]$$ concentration?

Accepted Answer

11.4

Question 19

What is the pH of a buffer that contains 0.15 M CH$$_3$$COOH and 0.10 M NaCH$$_3$$COO ($$K_a = 1.75 	imes 10$$^{-5}$$)?

pH = pK_a$$ + \log \left( \frac{[A^-]}{[HA]} ight)$$

Accepted Answer

4.58

Question 20

Which of the following pairs make up a buffer?

Accepted Answer

HCO3$$^-$$ and CO3$$^{2-}$$

Question 21

Which salt forms a basic solution when dissolved in water?

Accepted Answer

Na3PO4

Question 22

What is the molarity of an HCl solution if 43.6 mL of a 0.125 M KOH solution are needed to titrate a 25.0 mL sample of the acid?

$$M_1V_1 = M_2V_2$$

Accepted Answer

0.218

Solutions, Solubility, and Acids & Bases: Key Concepts and Calculations

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