| Do not change the colour of turmeric<\/td> | Turn turmeric to red<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n Ques 2. Ammonia is found in many household products, such as window cleaners. It turns red litmus blue. What is its nature?<\/strong><\/p>\n\n\n\nAns: <\/strong>Window cleaners are basic in nature as basic solutions turn red litmus to blue.<\/p>\n\n\n\nQues 3. Name the source from which litmus solution is obtained. What is the use of this solution?<\/strong><\/p>\n\n\n\nAns:<\/strong> Litmus is obtained from Lichens.<\/p>\n\n\n\nLitmus solution tests the acidic and basic nature of any substance. The acidic solution turns blue litmus red, whereas, a basic solution turns red litmus blue. <\/p>\n\n\n\n Ques 4. Is the distilled water acidic\/basic\/neutral? How would you verify it?<\/strong><\/p>\n\n\n\nAns: <\/strong>Distilled water is neutral. To verify it we can use litmus paper. As the distilled water will not change the colour of red or blue litmus paper, it can be proved that it is neutral. <\/p>\n\n\n\nQues 5. Describe the process of neutralisation with the help of an example.<\/strong><\/p>\n\n\n\nAns:<\/strong> When an acid solution and a base solution are combined in the right proportions, both the acidic and basic properties of the solutions are destroyed. The outcome is a neutral solution, neither acidic nor basic. This neutral solution is known as \u201cSalt\u201d and the reaction is known as \u201cNeutralisation Reaction\u201d. In the reaction, heat and water are also released.<\/p>\n\n\n\nQues 6. Which of the following statements are True or False:<\/strong><\/p>\n\n\n\na. Nitric acid turns red litmus blue.<\/strong><\/p>\n\n\n\nb. Sodium hydroxide turns blue litmus red.<\/strong><\/p>\n\n\n\nc. Sodium hydroxide and hydrochloric acid neutralise each other and form salt and water.<\/strong><\/p>\n\n\n\nd. The indicator is a substance which shows different colours in acidic and basic solutions.<\/strong><\/p>\n\n\n\ne. Tooth decay is caused by the presence of a base.<\/strong><\/p>\n\n\n\nAns: <\/strong><\/p>\n\n\n\na. False<\/p>\n\n\n\n b. False<\/p>\n\n\n\n c. True<\/p>\n\n\n\n d. True<\/p>\n\n\n\n f. False<\/p>\n\n\n\n Ques 7. Dorji has a few bottles of soft drinks in his restaurant. But, unfortunately, these are not labelled. 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?<\/strong><\/p>\n\n\n\nAns: <\/strong>Dorji will have to taste a few drops of soft drinks. He will observe that the acidic solution tastes sour, the basic solution tastes bitter, and the neutral solution tastes like nothing at all. Thereafter, Dorji can examine the nature of the soft drinks using litmus paper in addition to taste. He should check the acidic solution with blue litmus paper. To test the blue litmus, Dorji must apply a drop of solution. The solution is going to be acidic if it becomes red.<\/p>\n\n\n\nSimilar to that, he can test the fundamental solution using red litmus paper. On red litmus, he must dab a drop of the solution. If it becomes blue, the answer will be straightforward.<\/p>\n\n\n\n Ques 8. Explain why:<\/strong><\/p>\n\n\n\na. An antacid tablet is taken when you suffer from acidity.<\/strong><\/p>\n\n\n\nb. Calamine solution is applied on the skin when an ant bites.<\/strong><\/p>\n\n\n\nc. Factory waste is neutralised before being disposed it into the water bodies.<\/strong><\/p>\n\n\n\nAns:<\/strong><\/p>\n\n\n\na. An antacid tablet has base milk of magnesia which neutralises HCl present in our stomach. Owing to this, it is used when we suffer from acidity. <\/p>\n\n\n\n b. Ants inject formic acid into the skin when they bite. Calamine is made up of zinc carbonate, which is naturally basic. As a result, calamine balances the effects of formic acid to provide relief for the afflicted.<\/p>\n\n\n\n c. As factory wastes are acidic these can have an adverse impact on the aquatic flora and fauna. Thus, to reduce the impact of the acids, the wastes are neutralised by adding a base before disposing of wastes into seas and oceans. <\/p>\n\n\n\n Ques 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.<\/strong><\/p>\n\n\n\nAns: <\/strong><\/p>\n\n\n\n\n- When a turmeric indicator does not change its colour, then the solution is hydrochloric (HCl) acid. <\/li>\n\n\n\n
- Whereas, if the indicator turns to red the solution is either sodium hydroxide, a base, or a sugar solution, a neutral solution. <\/li>\n<\/ul>\n\n\n\n
Ques 10. Blue litmus paper is dipped in a solution. It remains blue. What is the nature of the solution? Explain.<\/strong><\/p>\n\n\n\nAns:<\/strong> The solution may be basic or neutral as both these will not transform the colour of the blue litmus paper. <\/p>\n\n\n\nQues 11. Consider the following statements:<\/strong><\/p>\n\n\n\na. Both acids and bases change the colour of all indicators.<\/strong><\/p>\n\n\n\nb. If an indicator gives a colour change with an acid, it does not give a<\/strong><\/p>\n\n\n\nchange with a base.<\/strong><\/p>\n\n\n\nc. If an indicator changes colour with a base, it does not change colour with an acid.<\/strong><\/p>\n\n\n\nd. Change of colour in an acid and a base depends on the type of the indicator.<\/strong><\/p>\n\n\n\nWhich of the above-mentioned statements is correct?<\/strong><\/p>\n\n\n\n(i) All four<\/strong><\/p>\n\n\n\n(ii) a and b<\/strong><\/p>\n\n\n\n(iii) b,c, and d<\/strong><\/p>\n\n\n\n(iv) Only d<\/strong><\/p>\n\n\n\nAns:<\/strong> Option (iv) Only d<\/p>\n\n\n\n |
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