Concept explainers
Calculate the pH after mixing 15 mL of 0.12 M acetic acid with 15 ml of 0.12 M NaOH. What are the major species in solution at equilibrium (besides water), and what are their concentrations?
Interpretation:
The
Concept introduction:
The
Hydronium ion concentration is calculated by considering the equilibrium conditions and from the value of acid dissociation constant.
The concentration of acetic acid and acetate ion is determined by using equilibrium condition The concentration of acetate ion and hydronium ion is equal at equilibrium according to the reaction stoichiometry.
Equilibrium constants:
The equilibrium constant is used to quantitative measurement of the strength of the acid and bases in the water.
The
The sum of
The
Answer to Problem 5CYU
The
The major species except water in the solution at equilibrium are
Explanation of Solution
An equilibrium constant
For any base B, the chemical reaction is written as,
The relative strength of an acid and base in water can be also expressed quantitatively with an equilibrium constant as follows:
An equilibrium constant
Given:
Refer to the table
Dissociation constant
The concentration of
The concentration of
The volume of
The volume of
The balanced chemical equation involving acetic acid and sodium hydroxide is written as,
Amount of
After completion of the reaction, the total volume of solution
The concentration of acetate ion is,
Therefore, the concentration of acetate ion is
Amount of
The concentration of sodium ion is,
Therefore, the concentration of sodium ion is
With the initial concentration of acetate ion is known, set up an ICE table to calculate the equilibrium concentration of hydroxide ion
Substitute the values at equilibrium from the ICE table into equation (3) to calculate the concentration of hydroxide ion,
Substitute the value
The acetate ion is the very weak base. Therefore,
Since the concentration of hydroxide ion is equal to
Substitute the concentration of hydroxide ion into equation (1) to calculate
Substitute the value of
Therefore, the
The major species besides water at equilibrium are
The
The major species besides water in the solution at equilibrium are
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Chapter 16 Solutions
Chemistry & Chemical Reactivity
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