ROUTERA

Acids,Bases and Salts

Class 10th Science Chapter Case Study

Case Study 1: The Use of Vinegar in Cooking

Case Description:
Vinegar, a common household item, is primarily composed of acetic acid (CH₃COOH). It is widely used in cooking for flavoring, preserving foods, and as a cleaning agent. Its acidic nature makes it effective in enhancing the taste of various dishes and preserving fruits and vegetables. Understanding the properties of vinegar and its reactions with other substances can help one appreciate its role in culinary practices and home remedies.

MCQs:

  1. What is the main active ingredient in vinegar?

    • A) Citric acid
    • B) Acetic acid
    • C) Lactic acid
    • D) Formic acid

  2. Which of the following is a characteristic property of acids?

    • A) Bitter taste
    • B) Slippery feel
    • C) Sour taste
    • D) High pH

  3. What happens when acetic acid reacts with baking soda?

    • A) No reaction occurs
    • B) Produces carbon dioxide gas
    • C) Produces hydrogen gas
    • D) Forms a salt and water

  4. Which of the following is an indicator that can be used to test the acidity of vinegar?

    • A) Turmeric
    • B) Litmus paper
    • C) Starch solution
    • D) Phenolphthalein

Case Study 2: The Role of Antacids

Case Description:
Antacids are medications used to neutralize stomach acid, providing relief from heartburn and indigestion. Most antacids contain basic compounds such as magnesium hydroxide, aluminum hydroxide, or calcium carbonate. When these bases interact with the hydrochloric acid in the stomach, they form salt and water, thereby reducing acidity and alleviating discomfort. Understanding how antacids work helps in making informed choices about their use.

MCQs:

  1. What is the primary purpose of antacids?

    • A) To increase stomach acid
    • B) To neutralize stomach acid
    • C) To stimulate digestion
    • D) To promote acid production

  2. Which of the following is a common active ingredient in antacids?

    • A) Sodium bicarbonate
    • B) Citric acid
    • C) Acetic acid
    • D) Lactic acid

  3. What type of reaction occurs when an antacid neutralizes stomach acid?

    • A) Synthesis reaction
    • B) Decomposition reaction
    • C) Neutralization reaction
    • D) Combustion reaction

  4. Which of the following is a potential side effect of overusing antacids?

    • A) Increased acidity
    • B) Kidney stones
    • C) Diarrhea
    • D) Dehydration

Case Study 3: The pH Scale and Its Importance

Case Description:
The pH scale is a numerical scale used to specify the acidity or basicity of an aqueous solution. It ranges from 0 to 14, where values less than 7 indicate acidity, a value of 7 is neutral, and values greater than 7 indicate alkalinity. Understanding the pH of various substances is important in fields such as medicine, agriculture, and chemistry. For instance, maintaining the proper pH in soil is essential for plant growth.

MCQs:

  1. What is the pH value of a neutral solution?

    • A) 0
    • B) 7
    • C) 14
    • D) 4

  2. Which of the following solutions is likely to have a pH less than 7?

    • A) Soap solution
    • B) Lemon juice
    • C) Baking soda solution
    • D) Distilled water

  3. What does a pH value of 3 indicate?

    • A) Neutral solution
    • B) Strongly acidic solution
    • C) Weakly acidic solution
    • D) Weakly basic solution

  4. How does the pH level affect plant growth?

    • A) It has no effect on plant growth.
    • B) It determines the availability of nutrients in the soil.
    • C) It affects only the color of plants.
    • D) It changes the temperature of the soil.

Case Study 4: The Formation of Salts

Case Description:
Salts are ionic compounds formed through the neutralization reaction between an acid and a base. Common table salt (sodium chloride) is a prime example, created when hydrochloric acid reacts with sodium hydroxide. Salts play significant roles in various industries, food preservation, and everyday life. Understanding the properties and types of salts can help us appreciate their applications in different fields.

MCQs:

  1. What is formed when hydrochloric acid reacts with sodium hydroxide?

    • A) Sodium bicarbonate
    • B) Sodium chloride
    • C) Sodium sulfate
    • D) Sodium phosphate

  2. Which of the following is a characteristic property of salts?

    • A) They have a sour taste.
    • B) They conduct electricity in solution.
    • C) They are always soluble in water.
    • D) They have a slippery feel.

  3. Which of the following methods is NOT used to prepare salts?

    • A) Neutralization
    • B) Direct combination
    • C) Electrolysis
    • D) Filtration

  4. Which type of salt is formed from a strong acid and a weak base?

    • A) Acidic salt
    • B) Basic salt
    • C) Neutral salt
    • D) Saline salt

Case Study 5: The Use of Litmus in Testing Acidity

Case Description:
Litmus is a natural pH indicator obtained from lichens, widely used to test whether a solution is acidic or basic. It changes color depending on the pH of the solution; it turns red in acidic solutions and blue in basic solutions. The simplicity and effectiveness of litmus paper make it a popular choice in laboratories and classrooms for quick testing of the acidity or basicity of various substances.

MCQs:

  1. What color does litmus turn in an acidic solution?

    • A) Blue
    • B) Red
    • C) Green
    • D) Yellow

  2. Which of the following substances would turn litmus paper blue?

    • A) Vinegar
    • B) Lemon juice
    • C) Soap solution
    • D) Hydrochloric acid

  3. Litmus paper is derived from:

    • A) A type of algae
    • B) Lichens
    • C) Fungi
    • D) Moss

  4. Which of the following is a limitation of using litmus paper?

    • A) It can only test strong acids.
    • B) It cannot determine the exact pH value.
    • C) It is not reusable.
    • D) It changes color with temperature.