Buffered solutions adding strong acid

For those combinations in exercise 49 that behave as buffered solutions, write equations showing how the components of the buffer consume added strong acid (HCl) or strong base (NaOH). 

When a strong base is added to a buffer solution, the weak acid H4 donates protons to hydroxide ions to form the conjugate base... 

Now suppose that we add 0.01 mol of HC1 to 1.00 L of the 0.10 M acetic acid-0.10 M sodium acetate buffer solution. The added strong acid will convert 0.01 mol of acetate ions to 0.01 mol of acetic acid because of the neutralization reaction... 

An acidic buffer solution has an excess of all the reactants and products, except for H30. Thus, when we try to change the concentration of H30 by adding strong acid or base, the equilibrium shifts, in accordance with LeChatelier s principle, to resist that change. The pH changes very little. (We will do calculations to show quantitatively how little the pH changes in such systems later in this section.)... 

A buffer solution contains a conjugate acid-base pair with both the acid and base in reasonable concentrations. The acidic component reacts with added strong bases. The basic component reacts with added strong acids. 

Buffer solution A solution that resists changes in pH when strong acids or strong bases are added. A buffer solution contains an acid and its conjugate base, so it can react with added base or acid. Common buffer solutions contain either (1) a weak acid and a soluble ionic salt of the weak acid or (2) a weak base and a soluble ionic salt of the weak base. 

Buffer solutions contain a base and an acid that can react with an added acid or base, respectively, and they maintain a pH very close to the original value. Buffers usually consist of approximately equal quantities of a weak acid and its conjugate base, or a weak base and its conjugate acid. For example, a buffer solution of acetic acid and its conjugate base, the acetate ion, can neutralize small amotmts of a strong acid or strong base as follows ... 

Which component of a buffered solution is capable of combining with an added strong acid Using your example from exercise 46, show how this component would react with added HCl. 

Describe a buffered solution. Give three examples of buffered solutions. For each of your examples, write equations and explain how the components of the buffered solution consume added strong acids or bases. Why is buffering of solutions in biological systems so important ... 

The scenes below depict solutions of the same HA/A buffer (with other ions and water molecules omitted for clarity), (a) Which solution has the greatest buffer capacity (b) Explain how the pH ranges of the buffers compare, (c) Which solution can react with the largest amount of added strong acid ... 

Therefore neither added strong acid nor added strong base alters the pH of the solution very much. Mixtures of this type are referred to as buffer solutions. 

Since the principal hazard of contamination of acrolein is base-catalyzed polymerization, a "buffer" solution to shortstop such a polymerization is often employed for emergency addition to a reacting tank. A typical composition of this solution is 78% acetic acid, 15% water, and 7% hydroquinone. The acetic acid is the primary active ingredient. Water is added to depress the freezing point and to increase the solubiUty of hydroquinone. Hydroquinone (HQ) prevents free-radical polymerization. Such polymerization is not expected to be a safety hazard, but there is no reason to exclude HQ from the formulation. Sodium acetate may be included as well to stop polymerization by very strong acids. There is, however, a temperature rise when it is added to acrolein due to catalysis of the acetic acid-acrolein addition reaction. 

A solution showing these properties is called a buffer, because it cushions the shock (Le0 the drastic change in pH) that occurs when a strong acid or strong base is added to water. 

The most important type of mixed solution is a buffer, a solution in which the pH resists change when small amounts of strong acids or bases are added. Buffers are used to calibrate pH meters, to culture bacteria, and to control the pH of solutions in which chemical reactions are taking place. They are also administered intravenously to hospital patients. Human blood plasma is buffered to pH = 7.4 the ocean is buffered to about pH = 8.4 by a complex buffering process that depends on the presence of hydrogen carbonates and silicates. A buffer consists of an aqueous solution of a weak acid and its conjugate base supplied as a salt, or a weak base and its conjugate acid supplied as a salt. Examples are a solution of acetic acid and sodium acetate and a solution of ammonia and ammonium chloride. 

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