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'''4. Buffered Solutions''' | '''4. Buffered Solutions''' | ||
A buffered solution resists changes in pH. The pH of a solution is a measure of its acidity, and is defined as the negative log of the hydrogen ion concentration. The pH scale ranges from 0 to 14 where 0 is the most acidic, 14 is the most basic, and 7 is neutral. Since pH is a log scale, the difference between pH 5 and pH 6, for example, is a factor of 10. Buffers are used when biological samples need to be kept within a narrow range of pH to maintain activity. The enzymes involved in biochemical reactions often require a narrow pH range. This range is usually 7.2–7.4 for human and animal tissues. A phosphate buffer is commonly used in the biology laboratory, because it exhibits excellent buffering capacity in the neutral pH range. It is made up of a mixture of sodium monobasic phosphate ( | A buffered solution resists changes in pH. The pH of a solution is a measure of its acidity, and is defined as the negative log of the hydrogen ion concentration. The pH scale ranges from 0 to 14 where 0 is the most acidic, 14 is the most basic, and 7 is neutral. Since pH is a log scale, the difference between pH 5 and pH 6, for example, is a factor of 10. Buffers are used when biological samples need to be kept within a narrow range of pH to maintain activity. The enzymes involved in biochemical reactions often require a narrow pH range. This range is usually 7.2–7.4 for human and animal tissues. A phosphate buffer is commonly used in the biology laboratory, because it exhibits excellent buffering capacity in the neutral pH range. It is made up of a mixture of sodium monobasic phosphate (NaH<sub>2</sub>PO4) and sodium dibasic phosphate (Na2HPO4) dissolved in water. | ||
=='''B. Solution Preparation'''== | =='''B. Solution Preparation'''== |
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