Acid Base Worksheets 3, 4, 5, 6 PDF

Worksheet 3 Turmeric indicator LO- To test acids and bases present in different food items by testing the samples with turmeric indicator. Part A I.Which of the following is an acid base indicator? a)vinegar b)Lime water c)Turmeric d)Baking soda II. Complete the following analo...

Worksheet 3 Turmeric indicator LO- To test acids and bases present in different food items by testing the samples with turmeric indicator. Part A I.Which of the following is an acid base indicator? a)vinegar b)Lime water c)Turmeric d)Baking soda II. Complete the following analogy Turmeric: Indicator Milk of magnesia: __Base___________ a)Acid b) base c) indicator d) none of the above III. You can determine the concentration of acids or bases in a solution by using a)the pH scale. b)salt. c) the periodic table of elements d)particle accelerator. IV.Turmeric is a natural indicator. On adding its paste to acid and base separately, which colours would be observed? a) Yellow in both acid and base b) Yellow in acid and red in base c) Pink in acid and yellow in base d) Red in acid and blue in base V. Radha decided to make a turmeric-based painting, but she doesn’t have any basic substance to draw the red part. Which household item will she use to make the red part of the painting? Ans.soap solution/baking soda VI. Consider the following statements: a) Both acids and bases change colour of all indicators. b) If an indicator gives a colour change with an acid, it does not give a change with a base. c) If an indicator changes colour with a base, it does not change colour with an acid. d) Change of colour in an acid and a base depends on the type of the indicator. Which of these statements are correct? i) All four ii) a and d iii) b and c iv) only d VII. Assertion (A) : Turmeric is a neutral natural indicator. Reason (R) : Turmeric acquires orange red colour in alkaline solution. a) Assertion and reason both are correct statement and reason is correct explanation for assertion. b) Assertion and reason both are correct statement and reason is not correct explanation for assertion. c) Assertion is correct statement but reason is wrong statement. d) Assertion is wrong statement but reason is correct statement. Section B 1. Why does turmeric stain on a cloth turn red when it is washed with soap?  Ans. Turmeric is a natural indicator which is yellow in color. It changes to red when dipped in a basic substance. Since soap is a base, turmeric stain on a cloth turn red when washed with soap 2. Three 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. Ans. To identify these solutions, firstly we will place turmeric in the given solution and the solution in which it turns red will be the base i.e. sodium hydroxide. The, we will add the base in the other two solutions i.e. hydrochloric acid and the sugar solution. The turmeric in the sugar solution will turn red upon addition of sodium hydroxide as the solution will turn basic. Whereas the turmeric in the hydrochloric solution will undergo no change as the solution will become neutral upon addition of the base and turmeric is yellow in acidic as well as neutral Worksheet 4 China rose indicator. Lo-To observe and analyze the acidic and basic nature of food items by testing the samples with China rose indicator. I. The most commonly used natural indicator is (a) turmeric (b) beetroot (c) China rose petal (d) litmus II.State whether true or false a)Acid solutions turns china rose indicator blue. False b) All substances are either acidic or basic. False III. China rose is a natural indicator of acids and bases. It turns green in basic conditions and dark pink in acidic conditions. The water, after one hour can be used as an indicator. It is light pink in neutral conditions. It turns green in basic conditions and dark pink in acidic conditions. Zeenat takes 10 ml of three colourless liquids in separate test tubes. She adds 5 drops of china rose indicator to each test tube.The pictures show the colour of the liquid in each test tube after the addition of indiators a. Which test tube contains liquid soap? Test tube 2 b. Why are china rose petals put in warm water to make the indicator? i. To darken the colour of the petals ii. To make the chemicals in the petals dissolve faster iii. To destroy the germs, present on the petals iv. To keep the petals fresh for a long time C. Why did Zeenat add the same amount of indicator to the three test tubes? Ans. To get accurate result. IV. Based on following diagram/picture answer the questions given below: In three test- tubes 'A', 'B', 'C' with solutions of different substances were added a few drops of China rose indicator. The colours shows in these test-tubes were magenta, colourless and green respectively Select the correct set indicating the substance whose solution are there in these test-tubes. A) B) A)Sugar solution A)Sugar solution B)Lime juice B)Lime water C)Lime water C)Lime juice C) D) A)Lime water A) Lime juice B)Sugar Solution B) sugar solution C)Lime juice C) Lime water VI. Assertion- China rose is a synthetic indicator. Reason- China rose turns green in alkaline solution. a) Assertion and reason both are correct statement and reason is correct explanation for assertion. b) Assertion and reason both are correct statement and reason is not correct explanation for assertion. c) Assertion is correct statement but reason is wrong statement. d) Assertion is wrong statement but reason is correct statement. Part B Answer the following. 1. How will you prepare China rose solution? Taking an example of any acid, base and neutral solution describe an activity to test the nature of above solutions using China rose indicator. Ans. Collect some China rose petals in a beaker and add some warm water. Keep the mixture for sometime till water becomes colored. This is known as china rose solution and is used as an indicator. Take some given sample in a test tube and pour some china rose indicator into it. The natural color of this indicator is pink. If it turns into dark pink or magenta the sample is acid and if it turns green the sample is a base. 2. Mehul, Gudia and their friend Rahul were provided with a test tube each Containing China rose solution which was pink in colour. Mehul added two drops of solution ‘A’ in his test tube and got dark pink (magenta) colour. Gudia added 2drops of solution ‘B’ to her test tube and got green colour. Rahul added 2 drops of solution ‘C’ but could not get any change in colour. Suggest the possible cause for the variation in their results. China rose is an acid-base indicator. Ans.China rose in different medium shows following reactions: China rose + acid ⟶ gives dark pink colour, hence solution 'A' is acidic in nature. China rose + base ⟶ gives green colour, hence solution 'B' is basic in nature. China rose + neutral ⟶ no change in colour, hence solution 'C' is neutral in nature. 3. Three beakers have different substances; you need to find which of the three is sodium hydroxide. You use china rose water to test. Identify which beaker had sodium hydroxide? Give reason Ans. As sodium hydroxide is a base and china rose solution changes to green in base solution so beaker 3 is the correct answer. Worksheet 5 The PH value of Acid and Bases LO-To observe and compare the acidic and basic nature of substances by testing the samples with PH indicator. I. Fill in the table according to your observations: Acid or Base or # Sample pPH paper colour pH Neutral 1 2  3 4 5 6 My learning- _________________________________________________ ___________________________________________________________ II. 2. What are the pH of the substances that make blue litmus red? a) 7 and above b) less than 7 c) Exactly 7 III) What are the pH of the substances that make red litmus blue? a) 7 and above b) less than 7 c) Exactly 7 IV) As the pH of an acid decreases, the strength of the acid _______ a) Increases b) Decreases c) Remains the same) V) Out of the following select an artificial or synthetic indicator that is pink in base. (a) Phenolphthalein (b) China rose (c) Turmeric (d) litmus VI) Assertion- the range of acid 0 – 0.6 and base 7.1 to 14. Reason- the range of acid and base are determined by Ph. a) Assertion and reason both are correct statement and reason is correct explanation for assertion. b) Assertion and reason both are correct statement and reason is not correct explanation for assertion. c) Assertion is correct statement but reason is wrong statement. d) Assertion is wrong statement but reason is correct statement. VII. Assertion : pH = 7 signifies pure water. Reason: pH of acetic acid is greater than 7. a) Assertion and reason both are correct statement and reason is correct explanation for assertion. b) Assertion and reason both are correct statement and reason is not correct explanation for assertion. c) Assertion is correct statement but reason is wrong statement. d) Assertion is wrong statement but reason is correct statement. Part B 1. You are provided with two test tubes containing baking soda solution, tamarind solution and litmus papers. Write down an activity to find the nature (acidic/basic/neutral) of each solution. Own answer Worksheet 6 To observe and analyze neutralization reaction by performing experiment with acid and base. Neutralization Part A I. Soha mixed equal amounts of two colourless liquids in a test tube. The colour of the liquids did not change. She observed the following: The test tube got hot. No gas bubbles were formed. No residue was formed in the test tube 1.Soha concluded that a chemical change took place in the test tube. Which change confirms her conclusion? a. The test tube got hot. b. No residue was formed. c. No gas bubbles were formed. d. The color change of the liquids did not change II. Complete the following chemical reaction. Acid + Base → X+Y Acid +base → salt + water What does X and Y stand for? X = ____Salt______________ Y = __Water___________________ III.Neutralization reaction is a (a) physical and reversible change b) physical change that cannot be reversed (c) chemical and reversible change (d) chemical change that cannot be reversed IV. State whether true or false a)The acidic or basic nature of a substance is tested by using an acid or base. False b)The substances which show different colours in acidic, basic and neutral solutions are called indicators. True V.Select the correct option for the following assertion-reason question: Assertion- the reaction between an acid and a base is known as neutralization reaction.Reason- the neutralization reaction forms salt and water as a product. a) Both A and R are true and R is the correct explanation of A. b) Both A and R are true but R is not the correct explanation of A. c) A is true but R is false. d) A is false but R is true. VI. A test tube is filled with a solution Y). When a few drops of phenolphthalein are added to this solution, the colour becomes pink. Identify the nature of Y a. acidic b. basic c. neutral Part B Answer the following. 1.What happens when an acidic solution is mixed with a basic solution? Ans. When an acidic solution is mixed with a basic solution, they neutralize each other forming salt and water. 2.After carrying out the neutralization reaction, the test tube immediately found to be somewhat hot. Explain why? Ans. In neutralization reaction between an acid and a base, heat is always produced. The evolved heat raises the temperature of reaction mixture due to which the tube becomes hot. 3.When hydrochloric acid is added to sodium hydroxide solution, sodium chloride and water are formed. a)Name this reaction. Neutralization reaction b)What changes in color will be observed when i)A strip of blue litmus paper is dipped in it. No change in colour ii) A strip of red litmus paper is dipped in it. No change in colour ii)What are neutral substances? Give example. Ans. A neutral substance is one which is not an acid or a base. All substances with a pH of 7 are neutral.For eg. Distilled water, salt water and sugar solution 4.Name the following: 1)Give an example of artificial indicator. Phenolphthalein 2)The natural indicator which changes to red in base and does not change in acid. Turmeric 3)The substance added to neutralize the basic nature of the soil. organic manure 4)The acidic liquid which an ant injects into the skin when it bites. Formic acid 5)The acid which helps us to digest food. Hydrochloric acid 6)The new substances formed during the neutralization reaction. Salt 7)An indicator obtained from the petals of China rose- China rose indicator 8. Two solutions are in test tube A and B. Drops of colourless indicator are added to both the test tubes. Test tube A changes to pink while Test tube B remains colourless. Identify the indicator and the nature of solution in A and B. Ans. Phenolphthalein is a colourless indicator it gives pink colour with a base. So Test tube A contains a base and test tube B may contain an acid or neutral solution. 9.During performing an experiment on neutralization reaction, Ravi took about 100 mL of sodium hydroxide solution and pour approximately the same amount of concentrated hydrochloric acid to it. He observed a very vigorous reaction with evolution of large amount of heat. When he dipped litmus paper into the solution it turned red. He was surprised with the result though he had read all the instructions and precautions given to him by his teacher a) What was the expected result of the experiment? Ans.The solution form will be neutral and would not change the colour of litmus. b) What went wrong in the experiment performed by Ravi? Ans.Ravi added concentrated hydrochloric acid instead of dilute hydrochloric acid.This mistake can prove very dangerous. c) Why Ravi observed a very vigorous reaction with evolution of large amount of heat when he added concentrated hydrochloric acid to sodium hydroxide? Ans. Hydrochloric acid is a strong acid and sodium hydroxide is a strong base to produce enough heat when mixed. In addition to this, Ravi used a concentrated form of this acid which can even cause a burn. d) What value of Ravi is shown here? Ans. Ravi showed carelessness over here by not reading the instructions and precautions carefully before experimenting. Worksheet 7 Neutralization in everyday life LO-To discuss and analyze the neutralization reactions happen in day to day life by giving various examples. Part A I. Which among the following can you drink if you have acidity in your stomach? Lime water, Orange Juice, Milk of Magnesia ………………………………………………………………………………………………… II.State true or false a) Phenolphthalein is a natural indicator. false b) Calamine can be used to treat ant’s sting. True III. When the soil is too basic, plants do not grow well in it. To improve its quality, what must be added to the soil? (a) Organic matter (b) Quicklime (c) Slaked lime (d) Calamine solution IV. Select the correct option for the following assertion-reason question: Assertion: Antacids neutralize the effect of extra acid produced in the stomach during indigestion and thus provide relief. Reason: Antacids are mild bases. a) Both A and R are true and R is the correct explanation of A. b) Both A and R are true but R is not the correct explanation of A. c) A is true but R is false. d) A is false but R is true. V.Assertion A): Toothpaste neutralizes the acid produced by fermentation of food particles in the mouth. Reason R): Toothpaste is alkaline in nature. a) Both A and R are true and R is the correct explanation of A. b) Both A and R are true but R is not the correct explanation of A. c) A is true but R is false. d) A is false but R is true. Part B Answer the following 1. Hydrochloric acid is a strong corrosive acid. Why then it is present inside our body? Ans. Due to the release of hydrochloric acid in the stomach, the pH of the stomach tends to decline in a range of 1.5 to 3. 1. This acidic condition is required for microbial digestion to prevent microbial diseases. 2. It is also helpful for the digestion of food particles. 2.Give reason a. An antacid tablet is taken when you suffer from acidity. Ans. Ans: The pain and discomfort due to acidity can be relieved by taking an antacid or base called milk of magnesia (contains magnesium hydroxide) which neutralizes the effect of excessive acid. b. Calamine solution is applied on the skin when an ant bite. Ans: When an insect bites, it injects the acidic liquid (formic acid). This acidic effect can be neutralized by applying base like calamine solution. (contains zinc carbonate) c. It is not advisable to drink lemonade during indigestion. Ans. Drinking lemon water is a potentially helpful remedy to reduce symptoms. Always drink it diluted and pay attention to the body's reaction. Some people report that drinking lemon water can reduce their symptoms of acid reflux after a meal. For others, lemon water can make their acid reflux worse. 3. If you are bitten by an ant, is it a good idea to take a soap bath? Give reason for your answer Ans. Ans. Soap being base helps to neutralize the affected area and reduces the pain caused due to the sting of ants /bees. The most common agent which is used in this type of wound is calamine solution which is alkaline and thus soothes the pain 4.A farmer is adding lime in his field, as shown in the picture. What might have happened to his field? Ans. Quicklime (CaO) is a basic oxide.It is sprinkled over acidic soil to raise its pH. Therefore, if the farmer is advised to sprinkle quick lime in his crop field, the soil would have been acidic and thus have a low pH. 5)Paheli was suffering from indigestion. Her mother took her to the doctor who told it is due the formation of too much ‘X’. Doctor prescribed a medicine ‘Y’ which relieved her from the pain and indigestion. a.Name the acid which helps us to digest food. Ans. Hydrochloric acid b.Identify the name of X and Y. X-acidity Y-milk of magnesia (contains magnesium hydroxide) c.Identify the nature of Y Base 6. Kishan observed that most of the fish in the pond of his village were gradually dying. He also observed that the waste of a factory in their village are flowing into the pond which probably caused the fish to die. a) Explain why the fish were dying ? Ans. The fish were dying because the factory waste in the water was acidic in nature. Fish cannot survive in such conditions that is acidic.  b) If the factory waste is acidic in nature, how can it be neutralized? Ans. The base will neutralize the acids. So, by adding the base (limestone, lime, etc) into water we can make it less harmful and neutral too. 7) What makes the soil acidic? How is soil treated to remove its too acidic or basic nature? Ans. The excessive use of fertilisers in the fields also makes the soil too acidic. When the soil is too acidic, it is treated with base such as quicklime (calcium oxide) or slaked lime (calcium hydroxide) which neutralises the excess acid present in the soil and reduces its acidic nature. If the soil is too basic, then decaying organic matter (called manure or compost) is added it. 8) Nitesh was playing with his friends in the garden. Suddenly, Nitesh was stung by a honeybee and was in great pain. Immediately, his friends call his mother. She applied baking soda solution to the affected area and then took him to the doctor. Read the above passage and answer the following questions: (a) What could be the reason for this burning pain? And. a) The reason for this burning pain is honeybee sting which causes pain and irritation. This is due to the acidic liquid (formic acid) injected into the skin by the honeybee (b) Why did his mother applied baking soda solution on the affected area? Ans. The effect of acid can be neutralized by rubbing the affected area by baking soda solution which is a mild base. (c) What values are shown by Nitesh’s friends? Ans. Nitesh’s friends are caring , supportive and helpful. 9. One day Rahul’s mother, after taking meal felt pain and irritation in her stomach. His father was out of station. Rahul was an intelligent boy. He remembered his teacher’s statement and gave his mother some baking soda solution Which gave her a relief from pain and irritation of stomach. Read the above passage and answer the following questions. (a) Rahul knows that our stomach contains hydrochloric acid. It helps us to digest food. But, too much acid in the stomach causes indigestion. Sometimes, indigestion is painful and some mild base should be taken to relief from this pain. So, this information given by his teacher helped him. (b) He gave her mother baking soda solution which was available in the kitchen easily. He selects baking soda because it is a mild base and neutralises the excess acid in the stomach and it will give relief from pain. (c) Rahul is very intelligent and caring boy.