Chapter 10: Acids and Bases and Equilibrium

Determine each of the following for a 0.100 M HBr solution:

a. $\left[{\mathrm{H}}_3{\mathrm{O}}^{+}\right]$

b. pH

c. the balanced chemical equation for the reaction with LiOH

d. millilitres of the HBr solution required to neutralize 36.0 mL of a 0.250 mL of LiOH solution

A 0.204 M NaOH solution is used to titrate 50.0 mL of an ${\mathrm{H}}_3{\mathrm{PO}}_4$solution.

a. Write the balanced chemical equation.

b. What is the molarity of the ${\mathrm{H}}_3{\mathrm{PO}}_4$solution if 16.4mL of the NaOH solution is required?

1. Write the formula for the conjugate acid for each of the following bases:

a.${\mathrm{CO}}_3^{2-}$

b.${\mathrm{H}}_2\mathrm{O}$

c.${\mathrm{H}}_2{\mathrm{PO}}_4^{-}$

d.${\mathrm{Br}}^{-}$

A 0.312 M KOH solution is used to titrate 15 mL of an ${\mathrm{H}}_2{\mathrm{SO}}_4$solution.

a. Write the balanced chemical equation.

b. What is the molarity of the ${\mathrm{H}}_2{\mathrm{SO}}_4$solution if 28.2 mL of KOH solution is required?

One of the most acidic lakes in the United States is Little Echo Pond in the Adirondacks in New York. Recently, this lake had a pH of 4.2, well below the recommended pH of 6.5.

a. What are the $\left[{\mathrm{H}}_3{\mathrm{O}}^{+}\right]\text{and}\left[{\mathrm{OH}}^{-}\right]$of Little Echo Pond?

b. What is the $\left[{\mathrm{H}}_3{\mathrm{O}}^{+}\right]\text{and}\left[{\mathrm{OH}}^{-}\right]$of a lake that has a pH of 6.5?

c. One way to raise the pH (and restore aquatic life) is to add limestone $CaC{O}_3$. How many grams of $CaC{O}_3$are needed to neutralize $1.0kL$ of the acidic water from Little Echo Pond if the acid is sulfuric acid?

localid="1654602249030" ${\mathrm{H}}_2{\mathrm{SO}}_4\left(aq\right)+{\mathrm{CaCO}}_3\left(s\right)⟶{\mathrm{CO}}_2\left(g\right)+{\mathrm{H}}_2\mathrm{O}\left(l\right)+{\mathrm{CaSO}}_4\left(aq\right)$

The daily output of stomach acid (gastric juice) is 1000 ml to 2000ml. Prior to a meal, stomach acid (HCl) typically has a pH of 1.42.

a. What is the $\left[{\mathrm{H}}_3{\mathrm{O}}^{+}\right]$of stomach acid?

b. One chewable tablet of the antacid Maalox contains 600mg of$CaC{O}_3$Write the neutralization equation and calculate the milliliters of stomach acid neutralized by 2 tablets of Maalox.

c. The antacid milk of magnesia contains 400 mg per teaspoon. Write the neutralization equation, and calculate the number of milliliters of stomach acid neutralized by 1 tablespoon of milk of magnesia ( 1 tablespoon =3 teaspoons).

Write the formula for the conjugate acid for each of the following bases:

a.${\mathrm{SO}}_4^{2-}$

b.$C{N}^{-}$

c.$N{H}_3$

d.$Cl{O}_2^{-}$

Identify the Brønsted-Lowry acid-base pairs in each of the following equations:

$$\begin{gathered} a)H_{2}C{O}_3(aq)+H_{2}O(l)\rightleftarrows HC{O}_3^{-}(aq)+H_3{O}^{+}(aq\left) \\ b\right)N{H}_3^{+}\left(aq\right)+H_{2}O\left(l\right)\rightleftarrows N{H}_3\left(aq\right)+H_3{O}^{+}\left(aq\right) \\ c)HCN(aq)+N{O}_2^{-}(aq)\rightleftarrows C{N}^{-}(aq)+HN{O}_2(aq) \end{gathered}$$

Identify the Bronsted-Lowry acid-base pairs in each of the following equations:

a.${\mathrm{H}}_3{\mathrm{PO}}_4\left(aq\right)+{\mathrm{H}}_2\mathrm{O}\left(l\right)\rightleftarrows {\mathrm{H}}_2{\mathrm{PO}}_4^{-}\left(aq\right)+{\mathrm{H}}_3{\mathrm{O}}^{+}\left(aq\right)$

b.localid="1652710222540" ${\mathrm{CO}}_3{}^{2-}(aq)+{\mathrm{H}}_2\mathrm{O}(l)\rightleftarrows {\mathrm{HCO}}_3^{-}(aq)+{\mathrm{OH}}^{-}(aq)$

c.localid="1652710226359" ${\mathrm{H}}_3{\mathrm{PO}}_4\left(aq\right)+{\mathrm{NH}}_3\left(aq\right)\rightleftarrows {\mathrm{H}}_2{\mathrm{PO}}_4^{-}\left(aq\right)+{\mathrm{NH}}_4^{+}\left(aq\right)$

Using Table $10.3$, identify the stronger acid in each of the following pairs:

a. $\mathrm{HBr}$or ${\mathrm{HNO}}_2$

b. ${\mathrm{H}}_3{\mathrm{PO}}_4$or ${\mathrm{HSO}}_4^{-}$

c. $\mathrm{HCN}$or ${\mathrm{H}}_2{\mathrm{CO}}_3$