Answer:
1. Answer: (d) nitrogen dioxide
Explanation: Nitrogen dioxide is non- metallic oxide hence it is acidic in nature and it has a pungent odour.
2. Answer: (a) CO2
Explanation: Three types of extinguishing agents are typically used—carbon dioxide, dry chemical, and foam water for fires involving flammable liquids, greases, and oils. Carbon dioxide is a compressed gas agent that prevents combustion by displacing the oxygen in the air surrounding the fire.
3. Answer: (b) add acid to water
Explanation:When we add water to acid, it releases some amount of energy. We can feel this energy by touching the surface of the test tube. Sometimes, released heat is too huge, because of this glasses of test tube may break down and acid can split over. So, in practice, you have to take an excessive amount of water and mix acid drop by drop. In this way, heat generated can be cooled down by this water and mistakes can be prevented.
4. Answer: (c) a salt and water
Explanation:The product of a neutralisation reaction is salt and water.
For example, hydrochloric acid reacts with sodium hydroxide to form sodium chloride salt and water.
5. Answer: (b) Yellow in acid and red in base
Explanation: Turmeric compound is a naturally occurring yellow color compound. It is an acid-base indicator, it remains yellow when acidic or neutral solutions are added to it.
6. Answer: (d) colourless and pink
Explanation: Phenolphthalein is a synthetic indicator and is weakly acidic in nature. When it is added to an acidic solution, it turns colourless. In the basic solution, it appears pink in colour.Phenolphthalein is colourless in acidic solution and pink in basic solution.
7. Answer: (a) Organic matter
Explanation: To improve quality and reduce the basic nature of the soil, the organic matter must be added to the soil. Organic matter releases acids that can neutralize the base of the soil and hence the quality of soil can be improved.
8. Answer: (d) Curd, vinegar
Explanation: Curd contains lactic acid and vinegar contains acetic acid. Lime water, soap and milk of magnesia are basic substances and grapes contains tartaric acid.
9. Answer: (c) Either acidic or neutral
Explanation: Phenolphthalein gives pink colour in basic solution. It remains colourless in acidic or neutral solution.Phenolphthalein only gives colour in basic medium.
10. Answer: (c) Turmeric
Explanation: Turmeric compound is a naturally occurring yellow colour compound. It is an acid-base indicator, turmeric compound remains yellow when acid or neutral solutions are added to it.
11. Answer: (d) Methyl chloride
Explanation: Methyl chloride cannot act as an indicator because it does not show any colour change in acidic or basic medium whereas methyl orange, phenolphthalein and turmeric are well-known indicators.
12. Answer: (d) Calcium carbonate
Explanation: Lime water is calcium hydroxide and when carbon dioxide is passed it reacts with calcium hydroxide to form calcium carbonate which turns lime water milky.
13. Answer: (c) Neutralisation reaction
Explanation: The reaction between acid and base produces salt and water, which is the example of neutralization reaction.
14. Answer: (a) Hydrogen ion
Explanation: The presence of hydrogen ions |H+| imparts acidic nature to HCl.
15. Answer: (a) Lactic acid
Explanation: Lactic Acid or milk acid is an organic acid with chemical formula C3H6O3. When milk sugar or lactose undergoes fermentation, the product obtained is lactic acid. It is found in cottage cheese, leban, sour milk, yogurt, and Koumiss.
16. Answer: (c) neutral
Explanation: Distilled water is neutral in character, i.e. it is neither acidic nor basic. Neutral nature of distilled water can be verified by the use of blue and red litmus paper.
17. Answer: (b) basic
Explanation: Ammonia turns red litmus to blue so it is basic in nature.
18. Answer: (b) acidity
Explanation: We take an antacid such as milk of magnesia to neutalises the excessive acid released in stomach.
19. Answer: (b) formic acid
Explanation: Formic acid, a component of ant venom uncommon in bee or wasp stings, is derived from the superfamily name Formicidae.
20. Answer: (c) lichens
Explanation: Litmus, mixture of coloured organic compounds obtained from several species of lichens that grow in the Netherlands, particularly Lecanora tartarea and Roccella tinctorum.
21.Answer: (d) boric acid
Explanation: Boric acid is often an ingredient in eye wash products. It's predominantly used as a mild antiseptic and to maintain the pH of the eye wash solution.
22. Answer: (c) milk of magnesia
Explanation: Magnesium hydroxide is an ingredient in OTC products, such as Milk of Magnesia. It also draws water into the intestines to help soften stool and encourage a bowel movement.
23. Answer: (b) lime water
Explanation: solutions of calcium hydroxide in water is known as lime water. Hence, Calcium Hydroxide {Ca(OH)2} is found in lime water.
24. Answer: (a) Carbonic acid
Explanation: Carbonic acid is added to soft drinks to make it fizzy. When the bottle is opened, the pressure decreases and the carbonic acid changes into carbon dioxide and water making it fizzy.
25. Answer: (b) Sodium hydroxide
Explanation: Sodium hydroxide is a strong base because it dissociates completely in an aqueous solution to form sodium cations, Na+, and hydroxide anions, OH−. Sodium hydroxide is completely ionic, containing sodium ions and hydroxide ions.
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