{"id":24289,"date":"2021-06-14T14:27:54","date_gmt":"2021-06-14T08:57:54","guid":{"rendered":"https:\/\/mcq-questions.com\/?p=24289"},"modified":"2022-03-02T10:38:22","modified_gmt":"2022-03-02T05:08:22","slug":"ncert-solutions-for-class-7-science-chapter-5","status":"publish","type":"post","link":"https:\/\/mcq-questions.com\/ncert-solutions-for-class-7-science-chapter-5\/","title":{"rendered":"NCERT Solutions for Class 7 Science Chapter 5 Acids, Bases and Salts"},"content":{"rendered":"

These NCERT Solutions for Class 7 Science<\/a> Chapter 5 Acids, Bases and Salts Questions and Answers are prepared by our highly skilled subject experts to help students while preparing for their exams.<\/p>\n

Acids, Bases and Salts NCERT Solutions for Class 7 Science Chapter 5<\/h2>\n

Class 7 Science Chapter 5 Acids, Bases and Salts Textbook Exercise Questions and Answers<\/h3>\n

Question 1.
\nState differences between acids and bases.
\nAnswer:<\/p>\n\n\n\n\n\n\n
Acids<\/td>\nBases<\/td>\n<\/tr>\n
1. Acid are sour to taste.<\/td>\na. Bases are bitter to taste.<\/td>\n<\/tr>\n
2. Acid turns blue litmus to red.<\/td>\nb. Base turns red litmus to blue.<\/td>\n<\/tr>\n
3. Acid is a substance which contains hydrogen ion (H+<\/sup>).<\/td>\nc. Bases contain hydroxide ions.<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

Question 2.
\nAmmonia is found in many household products, such as window cleaners. It turns red litmus blue. What is its nature?
\nAnswer:
\nAmmonia is basic in nature.<\/p>\n

Question 3.
\nName the source from which litmus solution is obtained. What is the use of this solution?
\nAnswer:
\nLitmus solution is a natural indicator which is obtained from lichens. It is used to determine whether a given solution is acidic or basic.<\/p>\n

Question 4.
\nIs the distilled water acidic\/basic\/ neutral? How would you verify it?
\nAnswer:
\nDistilled water is neutral. One can verify it by showing that neither red nor blue litmus paper changes its colour when dipped in distilled water.<\/p>\n

\"NCERT<\/p>\n

Question 5.
\nDescribe the process of neutralisation with help of an example.
\nAnswer:
\nThe reaction between an acid and a base to form salt and water with the evolution of heat is called neutralisation reaction. For example, when the solution of sodium hydroxide and hydrochloric acid react with each other, the acidic nature of acid and the basic nature of base are destroyed. The resulting solution is a neutral solution.<\/p>\n

Hydrochloric acid (HCl) + Sodium hydroxide (NaOH) \u2192 Sodium chloride (NaCl) + Water (H2<\/sub>O) + Heat<\/p>\n

In this reaction, the hydrogen ions from the acid reacts with the hydroxide ions of the base to from water and salt is formed.<\/p>\n

Question 6.
\nMake \u2018T\u2019 if the statement is true and \u2018F\u2019 if it is false:
\na. Nitric acid turns red litmus blue. (T\/F)
\nb. Sodium hydroxide turns blue litmus red. (T\/F)
\nc. Sodium hydroxide and hydrochloric acid neutralise each other and form salt and water. (T\/F)
\nd. Indicator is a substance which shows different colours in acidic and basic solutions. (T\/F)
\ne. Tooth decay is caused by the presence of a base. (T\/F)
\nAnswer:
\na. F,
\nb. F,
\nc. F,
\nd. T,
\ne. F.<\/p>\n

Question 7.
\nDorji has a few bottles of soft drink in his restaurant. But unfortunately, these are not labelled. He has to serve the drinks on the demand of customers. One customer wants acidic drink, another wants basic and third one wants neutral drink. How will Dorji decide which drink is to be served to whom?
\nAnswer:
\nDorji will take red and blue litmus papers and one by one dip them into each bottle of soft drink. The drink in which red litmus paper turns blue is the bottle of basic drink. The drink in which blue litmus paper turns red is the bottle of acidic drink. The drink in which both litmus papers show no changes in colour is of the neutral drink.<\/p>\n

Question 8.
\nExplain why:
\na. An antacid tablet is taken when you suffer from acidity.
\nb. Calamine solution is applied on the skin when an ant bites.
\nc. Factory waste is neutralised before disposing it into the water bodies.
\nAnswer:
\na. We take an antacid such as milk of magnesia to neutralise the excessive acid released in stomach during acidity.
\nb. Ant\u2019s sting contains an acid called formic acid and when we apply calamine solution containing a base, it neutralises the effect of acid and prevents irritation.
\nc. Many factories waste contain acids. If they are allowed to flow into the water bodies, the acids will kill the aquatic life. Therefore, factory waste is neutralised before its disposal.<\/p>\n

Question 9.
\nThree liquids are given to you. One is hydrochloric acid, another is sodium hydroxide and third is a sugar solution. How will you identify them? You have only turmeric indicator.
\nAnswer:
\nDip the turmeric indicator one by one in each liquid. The liquid in which the colour of turmeric indicator changes to red is basic in natural, i.e., sodium hydroxide. Since, we already identified sodium hydroxide. We will pour the sodium hydroxide in other two liquids. The liquid which gets warm after pouring the sodium hydroxide (base) solution in it is of hydrochloric acid as heat gets evolved in the process of neutralisation. The last one which shows no effect is the liquid of sugar solution.<\/p>\n

Question 10.
\nBlue litmus paper is dipped in a solution. It remains blue. What is the nature of the solution? Explain.
\nAnswer:
\nThere can be two cases:<\/p>\n