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Level 1 Worksheet: Acids, Bases & Salts

Class: 10 Science Topic: Reactions & Uses Max. Questions: 45
Name:
Date:
Section A: Conceptual Logic

Answer the following:

  1. Why does dry HCl gas not change the colour of dry blue litmus paper?
  2. While diluting an acid, why is it recommended that acid should be added to water and not vice versa?
  3. Why does an aqueous solution of acid conduct electricity?
  4. Compounds like alcohol and glucose also contain hydrogen but are not categorized as acids. Why?
  5. Why do basic solutions also have H$^+$(aq) ions? If yes, then why are they basic?
  6. Under what soil condition does a farmer treat the soil of his fields with quick lime (calcium oxide) or slaked lime (calcium hydroxide)?
  7. What is the function of tartaric acid in baking powder?
  8. Why should Plaster of Paris be stored in a moisture-proof container?
  9. Why does distilled water not conduct electricity, whereas rain water does?
  10. Fresh milk has a pH of 6. How do you think the pH will change as it turns into curd? Explain.
Section B: Reactions into Equations

Write balanced chemical equations for the following:

  1. Reaction of Zinc granules with dilute Sulphuric acid.
  2. Reaction of Zinc granules with Sodium Hydroxide solution. (Important)
  3. Reaction of Calcium carbonate with dilute Hydrochloric acid.
  4. Reaction of Sodium carbonate with dilute Hydrochloric acid.
  5. Passing excess Carbon dioxide through Lime water.
  6. Reaction of Copper Oxide with dilute Hydrochloric acid.
  7. Reaction of Sodium Hydroxide with Hydrochloric acid.
  8. Heating of Baking Soda (Thermal decomposition).
  9. Preparation of Bleaching powder.
  10. Recrystallisation of Sodium carbonate.
  11. Mixing Plaster of Paris with water.
Section C: Salts and Their Uses

Identify the Salt used for the following purposes:

  1. For disinfecting drinking water to make it free of germs.
  2. For making toys and materials for decoration.
  3. For removing permanent hardness of water.
  4. For making crispy pakoras in the kitchen.
  5. In soda-acid fire extinguishers.
  6. In glass, soap and paper industries.
  7. As an antacid to remove acidity.
  8. For supporting fractured bones.
  9. As a cleaning agent for domestic purposes (clothes).
  10. For bleaching wood pulp in paper factories.
Section D: Reasoning from Everyday Life

Explain the chemistry behind:

  1. When we are stung by a honey-bee, we feel pain and irritation. Applying mild base like baking soda gives relief. Why?
  2. Nettle leaves have stinging hair which cause painful stings. What is the natural remedy available in the wild?
  3. Why does a copper vessel get tarnished with a green coating in rainy season? (Actually Chapter 3, but related to basic carbonate).
  4. A milkman converts milk into curd. Why does he add a very small amount of baking soda to fresh milk?
  5. Why does the milk take a long time to set as curd if baking soda is added?