Answer the following:
Janani and her friends prepared turmeric paper by applying turmeric paste on filter paper and allowing it to dry. They then cut it into strips. They tested different household solutions such as lemon juice, soap solution, baking soda solution, sugar solution, and distilled water using the turmeric paper. They observed that in some solutions, the turmeric paper turned reddish-brown, while in others it remained yellow.
i. Which type of substances turn turmeric paper reddish-brown?
ii. What is the role of turmeric in this activity?