1. The pH of the gastric juices released during digestion is-
A. less than 7
B. more than 7
C. equal to 7
D. equal to 0
2. Which of the following phenomena occur, when a small amount of acid is added to water?
iv. Salt formation
A. 1 and 2
B. 1 and 3
C. 2 and 3
D. 2 and 4
3. Which one of the following can be used as an acid-base indicator by a visually impaired student?
C. vanilla essence
D. petunia leaves
4. Which of the following is acidic in nature?
A. lime water
B. human blood
D. lime juice
5. Which of the following substance will not give carbon dioxide on treatment with dilute acid?
C. baking soda
6. Calcium phosphate is present in tooth enamel. Its nature is-
7. A sample of soil is mixed with water and allowed to settle. The clear supernatent solution turns the pH paper yellowish –orange. Which of the following would change the colour of this pH paper to greenish-blue?
B. lemon juice
D. common salt
8. If a few drops of a concentrated acid accidentally spills over the hand of a student, what should be done?
A. wash the hand with saline solution
B. wash the hand immediately with plenty of water and apply a paste of sodium hydrogen carbonate
C. after washing with plenty of water apply solution of NaOH on the hand
D. neutralize the acid with a strong alkali
9. One of the constituents of baking powder is sodium hydrogen carbonate, the other constituent is –
A. acetic acid
B. hydrochloric acid
C. tartaric acid
D. sulphuric acid
10. To protect tooth decay, we are advised to brush our teeth regularly. The nature of the tooth paste commonly used is-