Telangana SCERT Class 7 Science Chapter 2 Solution – Acids and Bases. Here in this post we provides Class 7 Science Acids and Bases Telangana State Board Solution. Telangana State Board English Class VII Medium Students can download this Solution to Solve out Improve Your Learning Questions and Answers.
Telanagana State Board Class 7 Science Chapter 2 Acids and Bases Solution:
Question 1: The sting of a wasp is basic. How can we treat the sting of a wasp?
Ans. The sting of a wasp is basis to treat it we can use any diluted acidic substances.
We can also use toothpaste on effected area. Because toothpaste is a base, it will neutralize the acid in the sting.
Here is also another thing, its using by acetic acid and commonly called as venigar.
Question 2: Why are acids not stored in a metal container?
Ans. Acids reacts with metal and it produces hydrogen. so thats why acids are not stored in a metal containers.
Question 3: Acidic, basic and neutral solutions are given in three test tubes and you are given a strip of red litmus? How will you identify the three solutions?
Ans. At first dip the red litmus paper in all three test tubes. When it changes into blue it indicates basis solution. Now dip the blue one into other 2 test tubes when it changes into red that means the solution is acidic in nature. Then the last one in which the litmus does not change its color is a neutral one.
Question 4: When drops of lemon juice are put on blue litmus it turns red what will happen if you put some drops of soap solution on the same position on litmus paper?
Ans. When drops of lemon juice are put on blue litmus it turns red because of acids presence.
Now, when we will put some drops of soap solution on the same position mean on red litmus paper then the color of the litmus will turns into blue. The reason behind it, that bases turn red litmus into blue and soap solution is a base.
Question 5: What happens when Nitric acid is added to egg shell?
Ans. Egg shell is made of calcium carbonate. So when nitric acid is added to egg shell Calcium carbonate reacts with nitric acid and it gives carbon dioxide, calcium nitrate and water.
Question 6: Turmeric stains on white clothes, when washed with soap, turn red. Why?
Ans. Turmeric stains turned red when it washed with soap, because turmeric is a natural indicator and soap is basis in nature. When turmeric comes to contact with soap (base) then it turns red in color.
Turmeric + base (soap) —> turns red in colour.
Question 7: Ammonia is present in window cleaners. It turns red litmus blue. What is its nature.
Ans. This indicates that ammonia is basic in nature.
Question 8: What is the nature of urea? Is it acidic, basic / neutral? How can we verify it?
Ans. The nature of urea is basic nature of urea with the Litmus test. In Litmus test, Red litmus will turns into blue litmus. In this way we can verify it.
Question 9: Red litmus paper is dipped in a solution. It remains red. What is nature of the solution? Explain your answer?
Ans. The nature of the solution is acidic. Because only one reason, that is if we dip red litmus paper in the solution of basic, then it turns into blue. But if it did not turned to blue that it is acidic solution only.
Question 10: What is the effect of basic substances on turmeric paper?
Ans. When basic substances are applied on on termeric paper the yellow color turns into red colour, because termeric is a natural indicators. But when acids applied no change in color takes place.
Question 11: Can flowers and turmeric papers also be called indicators? Why?
Ans. Yes, they are also indicators because they change their color when they contact with acid or base.
Question 12: Correct the statement if it is wrong
- a) Indicators show different colours in acidic and basic solutions.
b)Sodium Hydroxide turns blue litmus red.
Ans. Sodium hydroxide is basic in nature. So it will turn red litmus into blue and it will have no effect on blue litmus paper and no color change will happen.
c) Tooth decay is caused by the presence of base.
ans. Tooth decay is caused due to the presence of acid.
Question 13: Take vinegar, lemon juice, soapy water, baking soda in different vessels. Put beetroot pieces in the vessels. Predict what happens? Verify your prediction by observing the changes. After 10 minutes, 30 minutes, 60 minutes record your observations. What do you conclude?
Ans. By this experiment, I would see that the vessel with that the vessel with vinegar and beetroot juice will turn the whole solution in red (park red). This because beetroot juice acts like an ]indicator of acids and base.
It turn all acids solutions in red.
So it will happen same in the case of lemon juice because it contains citric acid but the color is tight red. It happen also same with baking soda solutions. In the case of soapy water the solution in the vessel will turn blue when put the beetroot juice as because they are bases.
So i cam conclude that beetroot is an indicator which turns acidic solutions in red and basic solution in green.
Question 14: Visit a doctor. Find out the medicines she prescribes to treat acidity. Ask her how acidity can be naturally prevented. Prepare a report.
Ans. When we visit a doctor, she or he should prescribes antacid tablets like –
Acidity ca be naturally prevented by following this:
i) Drink plenty of water.
ii) Avoid Junk food.
iii) Take breakfast, lunch and dinner on time but keeping long intervals between then.
iv) Avoid to take acidic food.
V) Avoid high calories food.
vi) Drink a glass of milk everyday.
vii) Have vegetables like beans, cabbage, carrot etc…
Question 15: Prepare violet cabbage juice by boiling a piece of cabbage in water. Use it as an indicator and test acidic and basic solutions with it. Present your observations in the form of a table.
|Indicator||Acidic Solution||Basic Solution|
|violet cabbage juice||when it added in acetic solution it turns in color red / pink.||it added in basic solution then it turns solution then it turns in blue or green color.|
Question 17: Test the nature of lemon juice and milk sample with help of natural indicators prepared from different flowers. Explain their nature.
Ans. Lemon juice and milk both are acidic in nature, but lemon juice is more acidic than milk. Here use china rose petals it changes into colorless or same in color in acidic solution. Also use delphinium petals it changes to bluish red in acidic solution. In this way to test the nature of lemon juice and milk.
Question 18: How do you feel about nature? It is a big natural laboratory that contains innumerable indicators!
Ans. Nature is a wonderful creation of God. God made nature very beautiful.
There is in numerable indicators in this world and the nature is a big laboratory to contains all these.
These natural indicators are like turmeric, hibscus, litmus paper (chemical indicator) etc….
Question 21: Why industrial wastes are neutralised before releasing into water?
Ans. Industrial wastes are neutralised before releasing into water because they contains harmful acids and toxic chemicals, which may destroy the impurity of water bodies. And also it causes many diseases in human body indirectly. Here also the other reason that if this harmful acids discharged directly in water it will harm the ecosystem os water and aquatic animals also. It also imbalance the ph scale of water. So reduce the pollution and protect the water bodies they are neutralised.
6 CommentsAdd a Comment
Why do you don’t answered 19th and 20 questions
Why are not return 19th and 20th question
Why is there no 19th and 20th answers
i learned these question and answers and wrote my exams and passed
Harsh we are so glad to hear!
For Your next class You can read from Net Ex.
can we copy or download the answers for the students sake during the exam revisions.