ROUTERA

Acids,Bases and Salts

Class 10th Science Chapter Assertion and Reason

Acids,Bases and Salts

  • Options:
    a) Both Assertion (A) and Reason (R) are true, and Reason (R) is the correct explanation of Assertion (A).
    b) Both Assertion (A) and Reason (R) are true, but Reason (R) is not the correct explanation of Assertion (A).
    c) Assertion (A) is true, but Reason (R) is false.
    d) Assertion (A) is false, but Reason (R) is true.

 

Question 1

Assertion (A): Acids turn blue litmus paper red.
Reason (R): Acids release hydrogen ions (H⁺) in solution.

  • Answer: a) Both Assertion (A) and Reason (R) are true, and Reason (R) is the correct explanation of Assertion (A).
  • Explanation: Acids produce hydrogen ions when dissolved in water, which lowers the pH, causing blue litmus paper to turn red.

Question 2

Assertion (A): All acids have a sour taste.
Reason (R): The sour taste of acids is due to the presence of hydrogen ions.

  • Answer: b) Assertion (A) is true, but Reason (R) is false.
  • Explanation: While many acids do taste sour, not all acids should be tasted (e.g., strong acids can be harmful). The sour taste is generally associated with the presence of hydrogen ions, but tasting acids is not a safe practice.

Question 3

Assertion (A): Bases turn red litmus paper blue.
Reason (R): Bases release hydroxide ions (OH⁻) in solution.

  • Answer: a) Both Assertion (A) and Reason (R) are true, and Reason (R) is the correct explanation of Assertion (A).
  • Explanation: Bases produce hydroxide ions in solution, which raises the pH and causes red litmus paper to turn blue.

Question 4

Assertion (A): Sodium hydroxide is a strong base.
Reason (R): Sodium hydroxide completely dissociates into sodium ions and hydroxide ions in solution.

  • Answer: a) Both Assertion (A) and Reason (R) are true, and Reason (R) is the correct explanation of Assertion (A).
  • Explanation: Sodium hydroxide (NaOH) is a strong base because it fully dissociates in water, producing a high concentration of hydroxide ions.

Question 5

Assertion (A): Hydrochloric acid is used to clean metal surfaces.
Reason (R): Hydrochloric acid reacts with rust and other impurities to remove them.

  • Answer: a) Both Assertion (A) and Reason (R) are true, and Reason (R) is the correct explanation of Assertion (A).
  • Explanation: Hydrochloric acid (HCl) effectively reacts with iron oxide (rust) and other contaminants, cleaning metal surfaces.

Question 6

Assertion (A): Acids react with metals to produce hydrogen gas.
Reason (R): This reaction occurs because acids contain hydrogen ions that are displaced by metals.

  • Answer: a) Both Assertion (A) and Reason (R) are true, and Reason (R) is the correct explanation of Assertion (A).
  • Explanation: When acids react with reactive metals, hydrogen ions are displaced, resulting in the formation of hydrogen gas.

Question 7

Assertion (A): Salts are formed when acids react with bases.
Reason (R): This process is called neutralization, where an acid and a base react to form water and salt.

  • Answer: a) Both Assertion (A) and Reason (R) are true, and Reason (R) is the correct explanation of Assertion (A).
  • Explanation: Neutralization reactions between acids and bases yield salt and water, which is the basis for salt formation.

Question 8

Assertion (A): A solution with a pH of 7 is neutral.
Reason (R): Neutral solutions contain equal concentrations of hydrogen ions and hydroxide ions.

  • Answer: a) Both Assertion (A) and Reason (R) are true, and Reason (R) is the correct explanation of Assertion (A).
  • Explanation: A pH of 7 indicates that the concentrations of hydrogen and hydroxide ions are equal, resulting in a neutral solution.

Question 9

Assertion (A): Vinegar is a dilute solution of acetic acid.
Reason (R): Acetic acid is a weak acid that does not fully ionize in solution.

  • Answer: a) Both Assertion (A) and Reason (R) are true, and Reason (R) is the correct explanation of Assertion (A).
  • Explanation: Vinegar contains about 4-8% acetic acid, which is classified as a weak acid because it does not completely dissociate in water.

Question 10

Assertion (A): Lactic acid is produced in muscles during intense exercise.
Reason (R): Lactic acid is a byproduct of anaerobic respiration when oxygen is limited.

  • Answer: a) Both Assertion (A) and Reason (R) are true, and Reason (R) is the correct explanation of Assertion (A).
  • Explanation: During strenuous exercise, the body may switch to anaerobic respiration, producing lactic acid as a result of the incomplete breakdown of glucose.

Question 11

Assertion (A): Litmus paper can be used to test the pH of a solution.
Reason (R): Litmus paper changes color depending on whether the solution is acidic or basic.

  • Answer: a) Both Assertion (A) and Reason (R) are true, and Reason (R) is the correct explanation of Assertion (A).
  • Explanation: Litmus paper is an indicator that turns red in acidic solutions and blue in basic solutions, allowing for pH testing.

Question 12

Assertion (A): Ammonium hydroxide is commonly used as a household cleaner.
Reason (R): Ammonium hydroxide is a strong base that effectively removes grease and stains.

  • Answer: b) Assertion (A) is true, but Reason (R) is false.
  • Explanation: Ammonium hydroxide (NH₄OH) is considered a weak base and is used as a cleaner due to its ability to dissolve grease, but it is not classified as a strong base.

Question 13

Assertion (A): Baking soda can be used to neutralize stomach acid.
Reason (R): Baking soda is a weak base that reacts with hydrochloric acid in the stomach.

  • Answer: a) Both Assertion (A) and Reason (R) are true, and Reason (R) is the correct explanation of Assertion (A).
  • Explanation: Baking soda (sodium bicarbonate) reacts with excess stomach acid (hydrochloric acid) to neutralize it, providing relief from heartburn.

Question 14

Assertion (A): Strong acids can conduct electricity when dissolved in water.
Reason (R): Strong acids fully dissociate into ions in solution.

  • Answer: a) Both Assertion (A) and Reason (R) are true, and Reason (R) is the correct explanation of Assertion (A).
  • Explanation: Strong acids ionize completely in water, producing free ions that allow for the conduction of electricity.

Question 15

Assertion (A): Bases can be slippery to touch.
Reason (R): The slippery texture of bases is due to their reaction with fats and oils.

  • Answer: a) Both Assertion (A) and Reason (R) are true, and Reason (R) is the correct explanation of Assertion (A).
  • Explanation: Bases can react with fats and oils, producing soap-like substances that feel slippery, which is characteristic of many basic solutions.

Question 16

Assertion (A): The pH of a strong acid is lower than 7.
Reason (R): The pH scale ranges from 0 to 14, with lower values indicating higher acidity.

  • Answer: a) Both Assertion (A) and Reason (R) are true, and Reason (R) is the correct explanation of Assertion (A).
  • Explanation: Strong acids have pH values below 7, indicating high acidity, while the pH scale signifies that lower values correspond to stronger acids.

Question 17

Assertion (A): Calcium carbonate reacts with hydrochloric acid to produce calcium chloride, water, and carbon dioxide.
Reason (R): This is an example of a double displacement reaction.

  • Answer: b) Assertion (A) is true, but Reason (R) is false.
  • Explanation: While calcium carbonate does react with hydrochloric acid producing calcium chloride, water, and carbon dioxide, it is not classified as a double displacement reaction; it is a type of acid-carbonate reaction.

Question 18

Assertion (A): Phenolphthalein is a common indicator used in acid-base titrations.
Reason (R): Phenolphthalein turns pink in basic solutions and remains colorless in acidic solutions.

  • Answer: a) Both Assertion (A) and Reason (R) are true, and Reason (R) is the correct explanation of Assertion (A).
  • Explanation: Phenolphthalein indicates the pH of a solution by turning pink in basic conditions and remaining colorless in acidic conditions, making it useful for titrations.

Question 19

Assertion (A): Vinegar can be used to dissolve mineral deposits.
Reason (R): Vinegar contains acetic acid, which reacts with calcium carbonate found in mineral deposits.

  • Answer: a) Both Assertion (A) and Reason (R) are true, and Reason (R) is the correct explanation of Assertion (A).
  • Explanation: Acetic acid in vinegar reacts with calcium carbonate in mineral deposits, dissolving them effectively.

Question 20

Assertion (A): The reaction of acids with metals is exothermic.
Reason (R): The energy released during the reaction is due to the formation of new bonds.

  • Answer: a) Both Assertion (A) and Reason (R) are true, and Reason (R) is the correct explanation of Assertion (A).
  • Explanation: The reaction of acids with metals is indeed exothermic, and energy is released when new bonds are formed between the products, such as hydrogen gas and salts.