Difference in pH value between hydrochloric acid and ethanoic acid.

Answer
1. Hydrochloric acid is a strong acid.
2. Therefore, acid can ionise completely in water
3. to produce high concentration of hydrogen ion
4. Ethanoic acid is a weak acid.
5. This acid can ionise partially in water
6. to produce low concentration of hydrogen ion
7.  When the concentration of hydrogen ion is higher, the pH value is lower