Hydrochloric acid was added from a burette to 20 cm³ of aqueous potassium hydroxide containing a few drops of Universal Indicator. The graph shows the pH during the addition of the acid.

1. aWhat was the pH of the potassium hydroxide at first? [1]
2. bState the colour of the Universal Indicator when 10 cm³ of acid had been added, and when 30 cm³ of acid had been added. [2]
3. cWhat volume of the acid was added to neutralise 20 cm³ of the alkali? [1]
4. dComment on the relative concentrations of the acid and alkali. [1]

You'll mark your own answer against the marking guide when you hand it in.