Calculating pH of a Strong Acid - Chemistry Problems

Calculating pH of a Strong Acid - Chemistry Problems A strong acid is one that completely dissociates into its ions in water. This makes calculating the hydrogen ion concentration, which is the basis of pH, easier than for weak acids. Heres an example of how to determine pH of a strong acid. pH Question What is the pH of a 0.025 M solution of hydrobromic acid (HBr)? Solution to the Problem Hydrobromic Acid or HBr, is a strong acid and will dissociate completely in water to H and Br-. For every mole of HBr, there will be 1 mole of H, so the concentration of H will be the same as the concentration of HBr. Therefore, [H] 0.025 M. pH is calculated by the formula pH - log [H] To solve the problem, enter the concentration of the hydrogen ion. pH - log (0.025)pH -(-1.602)pH 1.602 Answer The pH of a 0.025 M solution of Hydrobromic Acid is 1.602. One quick check to make sure your answer is reasonable is to verify the pH is closer to 1 than to 7 (certainly not higher than this.) Acids have a low pH value. Strong acids typically range in pH from 1 to 3.