Barrons SAT Subject Test Chemistry, 13th Edition

(Marvins-Underground-K-12) #1

  1. (B) The pH is −log[H+]. A 0.005 molar solution of H 2 SO 4 ionizes in a dilute


solution to release two H+ ions per molecule of H 2 SO 4. Therefore, the molar
concentration of H+ ion is 2 × 0.005 mol/L or 0.010 mol/L. Substituting this in
the formula, you have:

pH = −log [0.01] = −log [1 × 10−2]

The log of a number is the exponent to which the base 10 is raised to
express that number in exponential form:

−log [1 × 10−2] = −[−2] = 2
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