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NCERT Solutions for Class 7 Science Chapter 4 Acids Bases and Salts

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NCERT Solutions for Class 7 Science Chapter 4 Acids Bases and Salts - FREE PDF Download

Unlock the comprehensive study with Vedantu through the class 7 science chapter 4 NCERT Solutions. This gives access to the class 7 science chapter 4 question answers PDF elucidating fundamental principles crucial for understanding the subject's intricacies.

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By accessing acids bases and salts class 7 solutions, students gain comprehensive insights into the core concepts such as Natural indicators, neutralisation, and more outlined in the curriculum. Check out the revised CBSE class 7 science syllabus and get started with Vedantu’s NCERT Solutions for Class 7 Science to embark on a journey of academic excellence.

Access NCERT Solutions for Class 7 Science Chapter 4 Acids Bases and Salts

1. State differences between acids and bases.

Ans:

Feature

Acids

Bases

Taste

Sour

Bitter

Litmus Paper Effect

Turns blue litmus paper red

Turns red litmus paper blue

Feel

Not soapy

Soapy to the touch

pH Range

0 - 6

8 - 14

Chemical Behavior

Proton donors (release H+ ions)

Proton acceptors (release OH- ions)

Examples

Hydrochloric acid (HCl), sulfuric acid (H2SO4), citric acid (C6H8O7)

Sodium hydroxide (NaOH), potassium hydroxide (KOH), ammonia (NH3)



2. Ammonium is found in many household products, such as window cleaners. It turns red litmus blue. What is its nature?

Ans: The substances that turn red litmus blue are base. Therefore, ammonium is basic in nature.


3. Name the source from which litmus solution is obtained. What is the use of this solution?

Ans: Litmus solution is extracted from lichens and is used to test the acidic/basic nature of the solution.


4. Is the distilled water acidic/basic/neutral? How would you verify it?

Ans: Distilled water is neutral in nature. We can verify it by using litmus paper. When some drops of the distilled water are poured on red/blue litmus paper, its color remains the same.


5. Describe the process of neutralization with the help of an example.

Ans: Neutralization is a reaction between acids and bases. Acids and bases are opposites in nature, when they mix, they neutralize the effects of each other. The substance formed in the neutralization reaction is known as salt.

Example: $\underbrace{HCl}_{acid}+\underbrace{NaOH}_{base}\to \underbrace{NaCl}_{salt}+\underbrace{{{H}_{2}}O}_{water}$.

 

6. Mark ‘T’ if the statement is true and ‘F’ if it is false.

(i) Nitric acid turns blue litmus red.

Ans: True, Nitric acid is acidic in nature and therefore it turns blue litmus red.

(ii) Sodium hydroxide turns blue litmus red. 

Ans: False, Sodium hydroxide is basic in nature and therefore it turns red litmus blue.

(iii) Sodium hydroxide and hydrochloric acid neutralize each other and form salts and water. 

Ans: True

$\underbrace{HCl}_{acid}+\underbrace{NaOH}_{base}\to \underbrace{NaCl}_{salt}+\underbrace{{{H}_{2}}O}_{water}$

Neutralization is a reaction between acids and bases, when they are mixed, they neutralize the effects of each other. 

(iv) An Indicator is a substance that shows different colors in acidic and basic solutions. (T/F)

Ans: True, Litmus is an indicator and it shows different colors in acidic and basic solutions.

(v) Tooth decay is caused by the presence of a base. (T/F)

Ans: False, Tooth decay is caused by the presence of an acid produced by bacteria.


7. Dorji has a few bottles of soft drinks in his restaurant, but unfortunately, these are not labeled. He has to serve the drinks on the demand of customers. One customer wants an acidic drink; another wants a basic and the third one wants a neutral drink. How will Dorji decide which drink is to be served to whom?

Ans: Dorji can use the indicator like litmus which can help him take the informed decision. If a few drops of a drink change blue litmus to red then it is acidic in nature and if it turns red litmus to blue then it is basic in nature. 

Also, if the drops of a drink do not affect the litmus, then it is neutral in nature.


8. Explain why:

(a) An antacid tablet is taken when you suffer from acidity.

Ans: An antacid tablet is taken when you suffer from acidity because the antacid tablet is basic in nature; it reacts with the excess acid in our stomach causing a neutralization reaction. Hence, it relieves us from the pain of acidity.

(b) Calamine solution is applied to the skin when an ant bites.

Ans: Calamine solution is applied on the skin when ant bites because ant bites inject acid in the skin and calamine solution is basic in nature, it reacts with the acid causing a neutralization reaction. Hence, it relieves us from itching and irritation.

(c) Factory waste is neutralized before disposing it into the water bodies.

Ans: Factory waste is neutralized before disposing it into the water bodies because excess acids or bases can be dangerous and fatal for the organisms living in the water.


9. Three liquids are given to you. One is hydrochloric acid, another is sodium hydroxide and the third is a sugar solution. How will you identify them? You have only a turmeric indicator.

Ans: Turmeric is acidic in nature and so it will turn red in contact with a base. From this, we can figure out that sodium hydroxide is a base. 

Now we are left with sugar solution and hydrochloric acid. The red spot created on the litmus due to the base will again turn yellow while in contact with an acid. You will observe that the hydrochloric acid will turn the red spot into yellow again and hence it is an acid. 

Sugar solution will not affect the litmus and hence it is a neutral solution.


10. Blue litmus paper is dipped in a solution. It remains blue. What is the nature of the solution? Explain.

Ans: We know that acids turn blue litmus into the red. When a blue litmus paper is dipped in a solution and it remains blue then the solution cannot be acidic. 

Hence, the solution can either be basic or neutral.


11. Consider the following statements:

(a) Both acids and bases change color at all indicators.

(b) If an indicator gives a color change with an acid, it does not give a change with a base.

(c) If an indicator changes color with a base, it does not change color with an acid.

(d) The change of color in an acid and a base depends on the type of indicator.

Which of these statements are correct?

(i) All four 

(ii) a and b 

(iii) b and c 

(iv) only d

Ans: (iv) Only d

Litmus is an indicator and it changes red to blue for the basic solution and blue to red for an acidic solution.

The same is with turmeric. It changes yellow to red for the basic solution.


Topics Covered in Science Chapter 4 Acids Bases and Salts Class 7

List of Topics Covered in Science Chapter 4 Class 7

Topics

Subtopics

Acids and Bases


Natural Indicators Around Us

Litmus: A natural dye, turmeric, china rose

Neutralisation


Neutralisation In Everyday Life

Ant bite, soil treatment, factory wastes



Benefits of NCERT Solutions for Class 7 Science Chapter 4 Acids Bases and Salts

To score good marks in science, it is always essential to study your NCERT textbook word by word and understand every concept mentioned in it. Vedantu experts provide the solutions of science class 7 chapter 4 question answers for a better understanding of students.


  1. Class 7 chapter 4 Science will help you fetch a deeper knowledge of all the questions. 

  2. You can download the class 7 science chapter 4 PDF question answers at any time at your convenience. 

  3. You can work hard and prepare efficiently for your exams by revising and practising all the NCERT questions. 

  4. This science class 7 chapter 4 question answers PDF provides you not just with correct answers but also guides you about the proper presentation of answers that will help you fetch good marks.

  5. Class 7 science chapter 4 acids bases and salts concepts are explained in detail through various scientific experiments. 

  6. Acids and bases, Natural Indicators Around Us, such as Litmus: A Natural Dye. Some more natural indicators explained in this chapter are Turmeric and China Rose.


Important Study Material Links for Class 7 Science Chapter 4 Acids Bases and Salts


Conclusion

The NCERT Solutions for Class 7 Chapter 4 science Acids, Bases and Salts, provided by Vedantu, is a valuable tool for Class 7 students. It helps introduce Science concepts in an accessible manner. The provided class 7 science chapter 4 acids bases and salts explanations simplify complex ideas, making it easier for Class 7 Students to understand the material. By using Vedantu's resources, Students can develop a deeper understanding of NCERT concepts. These class 7 science chapter 4 PDF question answers are a helpful aid for grade 10 students, empowering them to excel in their studies and develop a genuine appreciation for Acids, Bases and Salts.


NCERT Solutions for Class 7 Science - Other Chapter-wise Links

Dive into our collection of FREE PDF links offering other chapter-wise NCERT solutions, prepared by Vedantu Experts to help you understand and master fundamental scientific concepts.



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FAQs on NCERT Solutions for Class 7 Science Chapter 4 Acids Bases and Salts

1. What is the difference between acids and bases as per NCERT Solutions for Class 7 Science Chapter 4?

  • Acids taste sour, turn blue litmus red, and release H+ ions in water. Examples: Hydrochloric acid (HCl), citric acid.
  • Bases taste bitter, feel soapy, turn red litmus blue, and release OH- ions in water. Examples: Sodium hydroxide (NaOH), ammonia (NH3).

2. How do natural indicators help to identify acids and bases, according to Class 7 Science Chapter 4?

Natural indicators such as litmus, turmeric, and china rose exhibit color changes in the presence of acids and bases. For example, litmus extracted from lichens turns red with acids and blue with bases. This helps to distinguish between acidic and basic substances easily.

3. Why is neutralization important in everyday life? Include an example from the Class 7 Acids Bases and Salts NCERT Solutions.

Neutralization prevents harm from excess acids or bases. For example, an antacid tablet is taken when suffering from acidity; the base in the tablet neutralizes excess stomach acid, relieving discomfort.

4. What role do acids, bases, and salts play in the neutralization reaction discussed in Science Class 7 Chapter 4 NCERT Solutions?

Acids and bases react during neutralization to form salt and water. The reaction removes the acidic and basic properties, making the solution neutral. For example: HCl + NaOH → NaCl + H2O.

5. How can Dorji identify acidic, basic, and neutral drinks using indicators as per NCERT Class 7 Science Chapter 4?

Dorji can test each drink with litmus paper. A drink turning blue litmus red is acidic, red litmus blue is basic, and no color change indicates a neutral drink.

6. Differentiate between strong and weak acids and bases based on Class 7 Science Chapter 4 Acids, Bases and Salts NCERT Solutions.

  • Strong acids/bases completely dissociate into ions in water, e.g., HCl, NaOH.
  • Weak acids/bases partially dissociate in water, e.g., acetic acid (CH3COOH), ammonium hydroxide (NH4OH).

7. What is the function of calamine lotion when applied after an ant bite, as explained in Chapter 4 NCERT Solutions?

Calamine lotion is basic and neutralizes the acid injected by the ant bite through a neutralization reaction, so it reduces irritation and itching on the skin.

8. Why must factory wastes be neutralized before releasing into water bodies, as highlighted in Acids Bases and Salts Class 7 Solutions?

Factory wastes can be acidic or basic and may harm aquatic life. Neutralizing them prevents environmental damage by ensuring waste is safe before disposal.

9. According to NCERT Solutions for Class 7 Science Chapter 4, how can you use turmeric as an indicator to differentiate between common substances?

Turmeric changes color in contact with a base (turns red), stays yellow with acids or neutral substances. This property helps recognize if a solution is basic or not.

10. What does it mean when blue litmus paper remains blue after being dipped in a solution, as per Science Class 7 Chapter 4 NCERT Solutions?

If blue litmus paper remains blue, the solution is either basic or neutral, since only acids will turn blue litmus red.

11. Why is distilled water considered neutral, and how can we verify it as per Class 7 Science NCERT Solutions?

Distilled water is neutral because it does not change the color of red or blue litmus paper. Testing a drop on litmus paper confirms this as the color remains unchanged.

12. What is a salt according to the NCERT Solutions for Class 7 Science Chapter 4, and can you give an example?

A salt is a compound formed when an acid reacts with a base during neutralization. A common example is sodium chloride (NaCl), produced by reacting hydrochloric acid and sodium hydroxide.

13. Explain how indicators work differently in acidic and basic solutions as per your NCERT Solutions for Class 7 Science Chapter 4.

Indicators like litmus, turmeric, and china rose show distinct color changes in acids and bases. For example, litmus turns red in acid, blue in base, and turmeric turns red only in base, not in acid.

14. What misconceptions do students commonly have about acids, bases, and salts in Class 7 Science, and how does the NCERT Solutions chapter clarify them?

Common misconceptions include thinking all acids are dangerous or that only chemical indicators work. The chapter clarifies that edible items like lemon juice are acids, and natural indicators can identify acids and bases safely.

15. How does the NCERT Solutions for Class 7 Science Chapter 4 help students prepare for CBSE exams?

The Solutions provide step-by-step answers, clarify conceptual doubts, and follow the CBSE pattern, equipping students for exam questions and boosting confidence in solving textbook exercises efficiently.