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15 (a) Describe the difference between a strong acid and a weak acid - OCR Gateway - GCSE Chemistry: Combined Science - Question 15 - 2023 - Paper 9
Question 15
15 (a) Describe the difference between a strong acid and a weak acid. (b) Hydrochloric acid, HCl(aq), is an example of a strong acid. The graph shows the pH of a d... show full transcript
Worked Solution & Example Answer:15 (a) Describe the difference between a strong acid and a weak acid - OCR Gateway - GCSE Chemistry: Combined Science - Question 15 - 2023 - Paper 9
Step 1
Describe the difference between a strong acid and a weak acid.
Answer
A strong acid completely dissociates in water, releasing all of its hydrogen ions (H^+), which results in a high concentration of H^+ in the solution. This results in a low pH value. In contrast, a weak acid only partially dissociates in water, meaning that it releases fewer hydrogen ions. This results in a higher pH value compared to strong acids, making the solution less acidic.
Step 2
Step 3
Explain which method would be better to use for measuring the pH shown on the graph.
Answer
Using a pH meter would be better for measuring the pH shown on the graph as it provides more accurate and precise pH values compared to a universal indicator. While universal indicators can give a color representation of pH, they can be less reliable due to subjective interpretation of the color. A pH meter, on the other hand, gives a direct numerical value that eliminates ambiguity.