For the question, 'Explain why change in pH is less when 10ml of 0.1M Propanoic Acid is diluted to 100ml, then when 10ml of 0.1M Hydrochloric Acid is diluted to 100ml?
I've always thought that for weaker acids, diluting it would cause a greater pH change then stronger acids, due to really weak ionisation... (assuming my assumption is right...)