Fill in each blank with the correct word from the lesson.

1. If acids taste sour, _______ taste bitter — though you should never taste chemical substances to identify them.
2. Sodium hydroxide and potassium hydroxide are common _______.
3. When you take an antacid for in_______, the base in the tablet neutralises the excess hydrochloric acid in your stomach to relieve the burning sensation.
4. _______ hydroxide — slaked lime — is used for whitewashing walls and treating acidic soil.
5. Soap, baking soda, bleach, and ant_______ tablets are all bases.

Choose the best option for each question.

1. What happens to red litmus paper in a base?
   a) It stays redb) It turns bluec) It turns yellowd) It turns colourless
2. What is an alkali?
   a) Any baseb) A water-soluble basec) A strong acidd) A metal oxide
3. Why do antacid tablets relieve indigestion?
   a) They add more acidb) They absorb water from the stomachc) The base in them neutralises excess stomach acidd) They coat the stomach lining

Write T for True or F for False in the brackets.

1. It turns blue is one of the key concepts in the lesson on Bases and Alkalis.
2. It stays red is the main topic of this lesson.
3. A water-soluble base is one of the key concepts in the lesson on Bases and Alkalis.
4. Any base is the main topic of this lesson.

1. In your own words, explain what Bases and Alkalis means.
2. List two things you learned from this lesson on Bases and Alkalis.