pH Chemistry Example 4

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Example 4

medium
Compare a solution with pH 2 and a solution with pH 5. How many times greater is the hydrogen-ion concentration in the pH 2 solution?

Solution

  1. 1
    Each pH unit represents a factor of 10 change in hydrogen-ion concentration.
  2. 2
    The difference is 3 pH units, so the factor is 103=100010^3 = 1000. The pH 2 solution has 1000 times greater H+\text{H}^+ concentration.

Answer

1000 times greater.
The pH scale is logarithmic, not linear. A small numerical change in pH corresponds to a large multiplicative change in hydrogen-ion concentration.

About pH

A logarithmic scale ranging from 0 to 14 that quantifies the hydrogen ion concentration [H+][\text{H}^+] in an aqueous solution, where values below 7 indicate acidic.

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More pH Examples

Example 1 easy

Calculate the pH of a solution with [formula].

Example 2 medium

A solution has pH = 9. Calculate [formula] and [formula].

Example 3 medium

What is the pH of a [formula] HCl solution? (HCl is a strong acid.)

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