Acetic acid ionization

Acidic modifier Trifluoroacetic acid Formic acid Propionic acid Acetic acid Ionization completely suppressed Good separation/ionization Good separation/ionization Best separation/ionization... 

The correct answer is (A). This problem is an example of the common-ion effect. The weak acetic acid ionizes in water according to the following equation ... 

Psaki, C. and Carroll, J. Acetic acid ionization A study to determine the absorptive effects upon calcified tendonitis of the shoulder. Phys. Ther. Rev. 55 84, 1955. 

G. Acetic acid ionizes completely and ions remain in the water layer. 

Acetic acid (CH3COOH) has a of 1.76 X 10 at 25°C. Suppose 1.000 mol is dissolved in enough water to give 1.000 L of solution. Calculate the pH and the fraction of acetic acid ionized at equilibrium. 

Suppose that 0.00100 mol of acetic acid is used instead of the 1.000 mol in the preceding example. Calculate the pH and the percentage of acetic acid ionized. 

On the other hand, acetic acid (a weak acid) is only slightly ionized in dilute aqueous solution. Acetate ions have a strong tendency to react with H3O+ to form CH3COOH molecules. Acetic acid ionizes only slightly. 

When acetic acid ionizes, it dissociates to equal portions of H and OAc" by such an amount that the computation on the left side of Equation 7.20 will always be equal to 1.75 X lO- ... 

Use the data in Table 6.4 to calculate the enthalpy and entropy changes associated with aqueous acetic acid ionization (the third equation in the table), and examine the... 

When a weak electrolyte, such as acetic acid, ionizes in solution, we write the reaction in the form... 

Thus for substituted acetic acids in water at 25°, the maximum error to be expected is 0.015 a units. As S is probably about 0.1 and u — vch2x will generally be less than 0.30, the error in values obtained from acetic acid ionization constants should be negligible for most substituents. 

Now go back to that acetic acid equilibrium. The Kg for acetic acid is 1.8 x 10- . The Kg expression for the acetic acid ionization is... 

A 1.0 M solution of acetic acid ionizes less and has a higher concentration of ions than a 0.10 M acetic acid solution. Explain this behavior. (See Question 17 for data.)... 

The double arrow in the acetic acid ionization reaction indicates that the dissociation is incomplete, that is, a certain amount of undissociated acetic acid exists in solution with the dissociated acetic add. Acetic acid is called a weak add because it ionizes only to a limited extent in water. HCl and HNO3 are strong acids because they are, for all practical purposes, completely ionized in water. The relative strengths of acids and bases are discussed in detail in Section 11.2. 

Suppose you add HCl(o ) to this solution. What is the effect on the add-ionization equihbrium Because HCl(a ) is a strong acid, it provides H30 ion, which is present on the right side of the equation for acetic acid ionization. According to Le Chatelier s principle, the equilibrium composition should shift to the left. ... 

Initially, 1 L of solution contains 0.10 mol of acetic acid. Sodium acetate is a strong electrolyte, so 1 L of solution contains 0.20 mol of acetate ion. When the acetic acid ionizes, it gives x mol of hydronium ion and x mol of acetate ion. This is summarized in the following table ... 

In Chapter 15, we learned how to calculate the pH of a solution containing either a weak acid or its conjugate base, but not both. How do we calculate the pH of a buffer—sl solution containing both Consider a solntion that initially contains HC2H3O2 and NaC2H302, each at a concentration of 0.100 M. The acetic acid ionizes according to the reaction ... 

For example, a typical buffer can be made from the weak acid, acetic acid (HC2H3O2), and its salt, sodium acetate (NaC2H302). As a weak acid, acetic acid ionizes slightly in water to form H30 and a small amount of C2H302 . The addition of its salt provides a much larger concentration of the acetate ion (C2H302 ), which is necessary for its buffering capability. 

Often you will find that the ionization equilibrium with the largest K value is the most significant, hut this will not always be the case. The amounts of the various species in solution are also an important consideration. When one drop of 1.00 M H3PO4 (fCaj = 7.1 X 10-3) is added to 1.00 L of 0.100 M CH3COOH (iCa = 1.8 X 10 3), the acetic acid ionization is most important in establishing the pH of the solution. The solution contains far more acehc acid than it does phosphoric acid. 

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