Unit 10 Common Acids and Alkalis ETV 1

Unit 10 – Common Acids and Alkalis ETV

1. Why is it impossible for us to test whether something is acidic or not by our taste? Not everything is edible. Human is not sensitive towards acids and alkalis. Acids are tasteless. Alkalis are tasteless.

2. What are the colours of litmus paper? Red and blue Red and green Orange and green Yellow and green

3. State the colour change of litmus paper in acidic solution. From red to blue From blue to red From green to red From yellow to red

4. State the colour of phenolphthalein in acidic, alkaline and neutral solution respectively. Acidic – pink, neutral – colourless, alkaline colourless Acidic – colourless, neutral – colourless, alkaline pink Acidic – pink, neutral – pink, alkaline - colourless Acidic – pink, neutral – colourless, alkaline - blue

5. Which of the following description about the disadvantage of litmus paper, litmus solution and phenolphthalein is NOT correct? Their colour change cannot be observed easily. They cannot indicate acidity and alkalinity. Phenolphthalein is colourless under acidic and neutral environment. Red litmus solution remains red in colour in acidic and neutral environment.

6. The meaning of p. H = 0 is No p. H value neutral Very acidic Not acidic

7. Compared with p. H meter, which of the following is the disadvantage of universal indicator? It cannot indicate acidity and alkalinity. Colour change of universal indicator cannot be observed easily. Judging the colour with naked eye is not reliable. Universal indicator is toxic

8. According to the ETV programme, which of the following plant juice can act as indicator? Flowers of hydrangea and red cabbage Rose and flowers of hydrangea Flowers of hydrangea and cabbage Rose and grape

9. Which of the following is NOT a strong acid? Sulphuric acid Nitric acid Hydrochloric acid Citric acid

10. Which of the following domestic cleaner is not alkaline? Oven cleaner Toilet cleaner Class cleaner Sodium hydroxide

11. Which of the followings are precautions to be taken when handling strong acid or alkali? (I) they should be stored in higher shelves of the cabinet (II) gloves must be worn when using strong acids and alkalis. (III) Do not place them close to your face. (IV) ) They should only be used in places with good ventilation. (I) only (I)and (II) only. (II), (III)and (IV) only. (I), (III) and (IV)

12. Which of the following statement about diluting concentrated acid is NOT correct? A large amount of heat is released. The heat released turns water into steam. The steam combined with concentrated acid will splash. Dilution process causes the breakage of the beaker containing concentrated acid.

13. Which of the followings are the product of the reaction between vinegar and egg shell? (I) Water (II)Calcium acetate (III)Carbon dioxide (IV)Calcium oxide (I) only (II) and (III) only. (I), (II) and (III) (I), (III) and (IV)

14. Which of the following substances contain calcium carbonate? (I)Sea shells (II)Marble (III)Lime stone (IV)Baking powder (I) only (II) and (III) (I), (II), (IV)

15. State the name of the gas released when metal reacts with dilute acid. Carbon dioxide Hydrogen Oxygen Nitrogen

16. Which of the following about acid rain is NOT correct? Acid rain damages the structure of buildings and ruin sculptures. Acid rain affects the water environment Acid rain affects plant growth Acid rain is toxic and kill organisms in the environment.