During the Science Exhibition, four groups of students illustrated different activities related to acids and bases.
Group A added a few drops of lemon juice to blue litmus solution. The colour changed to red. They then added lime water drop by drop until the solution turned blue again.
Group B prepared a model showing that farmers add lime to fields where crops do not grow well because the soil has become acidic.
Group C explained that acidic liquid waste from factories is treated before it is released into rivers.
Group D demonstrated first aid by applying moist baking soda to the skin after a red ant bite.
After observing all the demonstrations, the teacher asked the students to identify the common scientific principle behind them and explain how the quantity of acid or base affects the final nature of the solution.
1. Suppose Group A stopped adding lime water immediately after the blue litmus turned red. What can be concluded about the solution? -
2. Which observation provides the strongest evidence that neutralisation has been completed in Group A's activity? -