16. Ions and Equilibrium;
       Acids and Bases
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Example. How many milliliters of a 0.10-molar NaOH solution will be required to neutralize 100 mil of 0.75-molar HCl

Solution. The amount of HCl present is

0.100 liter X 0.75 mole liter-1 = 0.075 mole HCl

Since each mole of HCI yields one mole of H+ upon complete dissociation, this quantity is also equal to 0.075 equivalent of HCl. For neutralization, the same number of equivalents of NaOH are required, 0.075. Again, since one mole of NaOH yields one mole of OH- upon dissociation, 0.075 equivalent of NaOH equals 0.075 mole. The volume of 0.10-molar NaOH required to produce this amount is

Just as milliliters are easier to use than liters in most situations because they replace decimal fractions with whole numbers, so millimoles (mmole) and milliequivalents (meq) often are more convenient than moles and equivalents; 1 mole = 1000 millimoles. The previous problem could be solved using millimoles and milliequivalents as follows:

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