What volume of water must be added to 14.4 mL of a pH 2.0 solution of HNO₃ in order to change the pH to 4.0? A) 14.4 mL B) 143 mL C) 1.43 × 10³ mL D) 36 mL E) 86 mL

Question

Quizplus · Accepted Answer

The pH scale is logarithmic, meaning that each unit change in pH corresponds to a tenfold change in hydrogen ion concentration. Moving from pH 2 to pH 4 represents a 100-fold decrease in hydrogen ion concentration. To achieve this, you would need to dilute the original solution by a factor of 100. Since the original volume is 14.4 mL, diluting it 100 times requires adding 99 times the original volume in water, which is 99 * 14.4 mL = 1425.6 mL. The closest answer to this calculation is 1.43 × 10^3 mL.

What Volume of Water Must Be Added to 14