Chapter 16 4 114 340 0150 Solution Nh3aq Titrated With

Chapter 16 – Acid-Base Equilibria and Solubility Equilibria

114. 340. mL of a 0.150 M solution of NH3(aq) is titrated with 0.100 M HCl. Calculate the

pH of the solution after 350. mL of HCl has been added. (Ka(NH4+) = 5.6 x 10–10)

115.

340. mL of a 0.150M solution of NH3(aq) is titrated with 0.100 M HCl. Calculate the pH of the solution after 750. mL of the

HCl has been added. (Ka(NH4+) = 5.6 x 10-10)

Chapter 16 – Acid-Base Equilibria and Solubility Equilibria

116. Select True or False: Bromothymol blue is a common acid-base indicator. It has a Ka

equal to 1.6  10–7. Its un-ionized form is yellow and its conjugate base is blue. At a pH of 5.8

the color in the solution would be yellow.

117. What would be the molar ratio of cyanic acid (HCNO)/sodium cyanate (NaCNO) buffer

having a pH of 4.80 ? [Ka(HCNO) = 2.0  10–4]

Chapter 16 – Acid-Base Equilibria and Solubility Equilibria

118. Calculate the molar solubility of silver carbonate. (Ksp (Ag2CO3 = 8.1 x 10–12))

119. Calculate the molar solubility of lead (II) fluoride. (Ksp (PbF2 = 4.1 x 10-8))

Chapter 16 – Acid-Base Equilibria and Solubility Equilibria

120. Select True or False: Solid sodium iodide is slowly added to a solution that is 0.0050 M

Pb2+ and 0.0050 M Ag+. [Ksp (PbI2) = 1.4  10–8; Ksp (AgI) = 8.3  10–17] AgI will precipitate

first.

Bloom’s Level: 4. Analyze

Difficulty: Medium

Gradable: automatic

Section: 16.07

Subtopic: Solubility Product (Ksp)

Topic: Solubility

121. Solid sodium iodide is slowly added to a solution that is 0.0050 M Pb2+ and 0.0050 M

Ag+. [Ksp (PbI2) = 1.4  10–8; Ksp (AgI) = 8.3  10–17] Calculate the Ag+ concentration when

PbI2 just begins to precipitate.

Chapter 16 – Acid-Base Equilibria and Solubility Equilibria

122. Solid sodium iodide is slowly added to a solution that is 0.0050 M Pb2+ and 0.0050 M

Ag+. [Ksp (PbI2) = 1.4  10–8; Ksp (AgI) = 8.3  10–17] What percent of Ag+ remains in

solution at this point?

123. The Ksp of CaF2 is 4  10–11. What is the maximum concentration of Ca2+ possible in a

0.10 M NaF solution?

Chapter 16 – Acid-Base Equilibria and Solubility Equilibria

124. 5.0 mL of 12 M NH3 is added to 500. mL of 0.050 M AgNO3. What concentration of

silver ion will exist after equilibrium is established? [Kf for Ag(NH3)2+ is 1.5  107.]

125. Select True or False: A precipitate of AgCl will form when 0.050 mol NaCl(s) and 0.050

mol AgNO3(s) are dissolved in 500. mL of 3.0 M NH3. [Kf for Ag(NH3)2+ is 1.5  107;

Ksp(AgCl) = 1.6  10–10]

Chapter 16 – Acid-Base Equilibria and Solubility Equilibria

126. Select True or False: There will be no Fe(OH)3 precipitate in a buffer solution that is

0.60 M CH3COOH and 0.10 M CH3COONa, if the solution is also made to be 0.001 M in

Fe3+. For Fe(OH)3, Ksp = 6.8  10–36.

127. The concentration of Mg2+ in seawater is 5.0  10–2 M. What hydroxide concentration is

needed to remove 90% of the Mg2+ by precipitation? (For Mg(OH)2, Ksp = 1.2  10–11.)

Chapter 16 – Acid-Base Equilibria and Solubility Equilibria

128. Calculate the equilibrium constant Kc for the following overall reaction:

AgCl(s) + 2CN–(aq) Ag(CN)2–(aq) + Cl–(aq)

For AgCl, Ksp = 1.6  10–10; for Ag(CN)2–, Kf = 1.0  1021.

129.

Calculate the equilibrium constant Kc for the net reaction shown below.

AgI(s) + 2NH3(aq) Ag(NH3)2+(aq) + I–(aq)

For AgI, Ksp = 8.3  10–17; for Ag(NH3)2+, Kf = 1.5  107.

Chapter 16 – Acid-Base Equilibria and Solubility Equilibria

130. The solubility of Ba(NO3)2 is 130.5 g/L at 0ºC. How many moles of dissolved salt are

present in 4.0 L of a saturated solution of Ba(NO3)2 at 0ºC?

131. A sample of rainwater collected near a lead smelter is analyzed for acid content.

Experiments show that a 100. mL sample of the rainwater is neutralized by 22.4 milliters of

0.0122 M NaOH. Assuming that the acid present is sulfurous acid, which resulted from the

reaction of SO2 with water, what is the molarity of acid in the rainwater?

Chapter 16 – Acid-Base Equilibria and Solubility Equilibria

132. An environmental chemist obtained a 200. mL sample of lake water believed to be

contaminated with a single monoprotic strong acid. Titrating this sample with a 0.0050 M

NaOH(aq) required 7.3 mL of the NaOH solution to reach the endpoint. What is the

concentration of H+ in the lake?

133. An environmental chemist obtained a 200. mL sample of lake water believed to be

contaminated with a single monoprotic strong acid. Titrating this sample with a 0.0050 M

NaOH(aq) required 7.3 mL of the NaOH solution to reach the endpoint. What is the pH of the

lake?

Chapter 16 – Acid-Base Equilibria and Solubility Equilibria

134. An environmental chemist obtained a 200. mL sample of lake water believed to be

contaminated with a single monoprotic strong acid. Titrating this sample with a 0.0050 M

NaOH(aq) required 7.3 mL of the NaOH solution to reach the endpoint. If the size of the lake

can be approximated as 1.1 km long by 2.3 km wide, and has an average depth of 10. m,

estimate how many moles of the strong acid are present in the lake?

135. NaCl is added slowly to a solution that is 0.010 M each in Cu+, Ag+, and Au+. The Ksp‘s

for CuCl, AgCl, and AuCl are 1.9  10–7, 1.8  10–10, and 2.0  10–13, respectively. Which

compound will precipitate first?

Chapter 16 – Acid-Base Equilibria and Solubility Equilibria

136. A 50.0 mL sample of 2.0  10–4 M CuNO3 is added to 50.0 mL of 4.0 M NaCN. The

formation constant of the complex ion Cu(CN)32– is 1.0  109. What is the copper(I) ion

concentration in this system at equilibrium?

137. How many moles of NaF must be dissolved in 1.00 liter of a saturated solution of PbF2 at

25C to reduce the [Pb2+] to 1.0  10–6 M? The Ksp for PbF2 at 25 C is 4.0  10–8.

Chapter 16 – Acid-Base Equilibria and Solubility Equilibria

138. At 25 C, the base ionization constant for NH3 is 1.8  10–5. Determine the hydroxide ion

concentration in a 0.150 M solution of ammonia at 25 C.

139. At 25 C, the base ionization constant for NH3 is 1.8  10–5. Determine the pH of a

solution prepared by adding 0.0500 mol of solid ammonium chloride to 100. mL of 0.150 M

ammonia.

Chapter 16 – Acid-Base Equilibria and Solubility Equilibria

140. At 25 C, the base ionization constant for NH3 is 1.8  10–5. Determine the percentage

ionization of a 0.150 M solution of ammonia at 25 C.

141. Select True or False: At 25 C, the base ionization constant for NH3 is 1.8  10–5. If

0.0800 mole of solid magnesium chloride is dissolved in a solution prepared by adding 0.0500

mol of solid ammonium chloride to 100. ml of 0.150 M ammonia, a precipitate of magnesium

hydroxide will form. (Assume the volume of the solution is unchanged. The solubility product

constant for magnesium hydroxide is 1.5  10–11.)

Chapter 16 – Acid-Base Equilibria and Solubility Equilibria

142. Select True or False: The percent ionization of a weak acid HA is greater in a solution

containing the salt NaA than it is in a solution of the weak acid only.

143. Select True or False: A mixture made from 10 mL of 1 M HCl and 20 mL of 1 M

CH3COONa would be classified as a buffer solution.

144.

Select True or False: All indicators are weak acids that are one color in acidic solution and another color in basic solution.

Chapter 16 – Acid-Base Equilibria and Solubility Equilibria

145. Select True or False: The solubility of a salt increases as its Ksp increases.

146. Select True or False: The pH of a solution that is 0.20 M CH3COOH and 0.20 M