APURVA TEACHING POINT
UNIT-TEST

(Science-X) Chap- 2

Timing: 30 minutes                                                                          M.M – 20

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One Mark questions:

 

Q1.    Why Sodium Hydrogen Carbonate is a main component of antacid?

         सोडियम हाइड्रोजन कार्बोनेट एंटासिड का मुख्य घटक होता है, क्यों ?

Q2.   Name the sodium compound which is used for softening hard water.

         उस सोडियम यौगिक का नाम बताइए जिसका उपयोग कठोर जल को मृदु बनाने में किया

        जाता है | 

Q3.    what is same in all acids? 

          सभी अम्लों में क्या समान होता है ? 

Q4.    write an example of reaction which product is used as fire extinguishers.

          एक अभिक्रिया का उदहारण दीजिये जिसके उत्पाद का उपयोग अग्नि-शामक के रूप में

          किया जाता है | 

 

Two Marks Question:

 

Q5.   Why should curd and sour substances not be kept in brass and copper vessels?

        ताम्बे या पीतल के वर्तन में दही या खट्टे पदार्थ क्यों नहीं रखना चाहिए ? 

Q6.   Why does distilled water not conduct electricity, whereas rain water does?

         आसूत जल विद्युत का चालन क्यों नहीं करता है, जबकि वर्षा जल करता है |

        स्पष्ट कीजिये | 

 

Three Marks question;

 

Q7.  Which gas is usually liberated when an acid reacts with a metal? Illustrate with an

        example. How will you test for the presence of this gas?

         अम्ल जब धातु के साथ अभिक्रिया करता है तो कौन-सी गैस निकलती है ? उदहारण देकर

         समझाइए | आप इस गैस की जाँच कैसे करेंगे | 

Q8.   What is chlor-alkali process? Give two uses of each products of this reaction.  

        क्लोर-क्षार अभिक्रिया क्या है ? इस अभिक्रिया के विभिन्न उत्पादों के दो-दो उपयोग लिखिए | 

Q9.    Write three applications of pH in our daily life. 

          हमारे दैनिक जीवन में pH के तीन उपयोग के बारे में लिखिए | 

Q10.  Give The answers of following questions;

          निम्न प्रश्नों का उत्तर दीजिये | 

          (i)  two important uses of washing soda.

               धावन सोडा के दो महत्वपूर्ण उपयोग लिखिए |

          (ii)  An example with equation of Neutralisation reaction. 

                एक उदासीनीकरण अभिक्रिया का समीकरण का उदहारण दीजिये | 

          (iii)  Why do acids not show acidic behaviour in the absence of water?

                जल की अनुपस्थिति में अम्ल अम्लीय व्यव्हार क्यों नहीं करता है ? 

 

 

Chapter 2. Acids, Bases and Salts

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Q1. Name two organic acids.

      दो जैविक अम्लों के नाम बताइए |

Q2. How does baking powder differ from baking soda?

       बेकिंग सोडा बेकिंग पावडर से अलग कैसे है ? 

Q3. What will happen if heating is not controlled while preparing plaster of Paris.

       क्या होगा जब प्लास्टर ऑफ़ पेरिस बनाते समय ऊष्मा नियंत्रित न हो | 

Q4. A housewife found that the cake prepared by her is hard and small in size. Which ingradient has she forgotten to add that would have made the cake fluffy. Give reason.

 एक गृहणी से पाया कि उसके द्वारा केक बनाते समय केक छोटा एवं कठोर रह गया है | वह कौन सा संघटक वह डालना भूल गयी थी जिससे यह केक फुला हुआ बन जाता | कारण दीजिए | 

Or 

A baker found that the cake prepared by him is hard and small in size. Which ingredients has he forgotten to add that would have caused the cake to rise and become light?

Q5. What is water of crystallization? Name two hydrated salts.

       जल के क्रिष्टिलीकरण क्या है ? दो हाइड्रेट लवणों का नाम दीजिए | 

Q6. What happens when an acid reacts with a base? Give equation of the reaction of the reaction involved. What is the special name of this reaction?

       क्या होता है जब कोई अम्ल किसी क्षारक के साथ अभिक्रिया करता है ? इस प्रकार के होने वाले अभिक्रिया का समीकरण लिखिए | इस अभिक्रिया का विशेष नाम क्या है ? 

Q7. Explain how pH changes in the river water can endanger the lives of aquatic animals.

       समझाइए कि कैसे नदी के जल का pH बदल जाता है और यह जलीय जीवों के जीवन के लिए कैसे खतरनाक है ?  

Q8. 

Q9. What are the two main ways in which common salt (sodium chloride) occurs in nature? How is common salt obtained from sea water? Explain.

      वे दो तरीकें कौन-कौन से है जिसमें साधारण नमक (सोडियम क्लोराइड) प्रकृति में बनता है ? साधारण नमक समुद्र से जल से कैसे प्राप्त होता है ? समझाइए | 

Q10. What happens when

(a) Solid sodium hydrogen carbonate is heated,

(b) Chlorine gas is passed through dry slaked lime,

(c) Gypsum is heated to a temperature of 373 K?

      क्या होता है जब 

(a) ठोस सोडियम हाइड्रोजन कार्बोनेट को गर्म किया जाता है | 

(b) शुष्क बुझे हुए चुने से क्लोरीन गैस प्रवाहित किया जाता है |

(c) 373 K के तापमान पर जिप्सम को गर्म किया जाता है | 

Q11. Answer the following;

(i) What is a salt?

(ii) Why aqueous solution of sodium carbonate is basic in nature?

(iii)Why is an aqueous solution of ammonium chloride acidic in nature?

निम्न प्रश्नों का उत्तर दीजिए | 

Q12. A milkman adds a very small amount of baking soda to fresh milk.

Q13. Why do acids not show acidic behaviour in the absence of water?

Q14. Alcohols and Glucose contain hydrogen but are not categorized as acids.

Q15. Plaster of Paris should be stored in a moisture-proof container. Explain why?

Q16. Why is calcium sulphate hemihydrates called 'Plaster of Paris'?

Q17. Equal lengths of the magnesium ribbons are taken in test tubes A and B. Hydrochloric acid (HCl) is added to test tube A, while acetic acid (CH3COOH) is added to test tube B. In which test tube will the fizzing occur more vigorously and why?

Q18. Name a solution reacts with crushed egg-shells to give a gas that lime-water milky.

Q19. Why does distilled water not conduct electricity, whereas rain water does.

Q20. What is aqua-regia ?

Q21. Name the sodium compound which is used for softening hard water.

Q22. Why should curd and sour substances not be kept in brass and copper vessels?

Q23. What is efflorescence?

Q24. What are the components of baking powder? 

Q25. Three solutions A, B and C have pH, values of 6, 4 and 10 respectively. Which of the solution is highly acidic?

Q26. Two solutions X and Y have pH = 4 and pH = 8 respectively. Which solution will give alkaline reaction and which one acidic.

Q27. A farmer has found that the pH of soil in his fields is 4.2. Name any two chemical materials which he can mix with soil with soil to adjust its pH.

Q28. State the chemical name and formula of common salt.

Q29. ‘Sweet tooth’ may lead to tooth decay. Explain why? What is the role of tooth paste in preventing cavities?

Q29. Write the reaction that takes place when sodium oxide reacts with water. How will this solution behave towards phenolphthalein and red litmus paper?

Q30. Why should curd and sour substances not be kept in brass and copper vessels? (2 marks) 8. How is the concentration of hydronium ions (H2O+) affected when a solution of an acid is diluted?

Q31. Why do acids not show acidic behavior in the absence of water?

Q32. Identify the compound of calcium which is used for plastering of fractured bones. With the help of chemical equation, describe how this compound is prepared. What special precaution should be taken during the preparation of this compound?

Q33. State Arrhenius Concept of acids and bases. Giving reason, select a strong acid and a weak base from amongst the following substances:

H2CO3, HNO3, NaOH, NH4OH

Q34.

(i) Why should curd and sour substances no be kept in brass and copper vessels.

(ii) The pH of hydrochloric acid solution is 3. Does it mean that it has only hydronium ions. If not, how are OH^- ions generated?

(iii) Distinguish between acid and alkali.  Or Compounds like alcohol and glucose also contain hydrogen but are not categorized as acids. Describe an activity to prove it.

Chapter 2. Acids, Bases and Salts

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Q1. What is the name given to a reaction between an acid and a base?

Q2. Name the raw materials used for preparing bleaching powder.

Q3. What is the chemical name and chemical formula of baking soda?

Q4. Under what soil conditions do you think a farmer would treat the soil of his fields with quick lime (calcium oxide) or slaked lime (calcium hydroxide) or chalk (calcium carbonate)?

Q5. What effect does the concentration of H+ (aq) have on the acidic nature of the solution?

Q6. A house-wife found that the cake prepared by her in hard and small in size. Which ingredient has she forgotten to add that would have made the cake fluffy. Give reason. 

Q7. Equal lengths of magnesium ribbon are taken in test tubes ‘A’ and ‘B’. Hydrochloric acid (HCI) is added to testtube A while acetic acid (CH3COOH) is added to test-tube ‘B’. In which test tube will the fizzing occur more vigorously and why?

Q8. Plaster of Paris should be stored in a moisture – proof container. Explain why?

Q9. Why do HCI, HNO3, etc. show acidic characters in aqueous solutions while solution of compounds like alcohol and glucose do not show acidic character?

Q10. You have been provided that three test-tubes? One of them contains distilled water and the other two contains an acidic solution and a basic solution respectively. If you are given red litmus paper, how will you identify contents of each test-tube?

Q11. A milkman adds a very small amount of baking soda to fresh milk”

(i) Why does he shift the pH of the fresh from ‘6’ to slightly alkaline?

(ii) What do you expect to observe when this milk comes to boil?

(iii) Why does this milk take a long time to set as cur?

Q12. A compound X of sodium form a white powder. It is a constituent of baking powder and is used in some antacid prescriptions. When heated, X gives out of a gas and steam. The gas forms a white precipitate with lime water. Write the chemical formula and name of X and the chemical equation for its decomposition on heating. What is its role in baking powder and in antacids?

Q13. Answer the followings.

(a) What is acid rain? How does it affect our aquatic life?

(b)What happens during a bee sting? What is its remedy?

(c)Two solutions X and Y are tested with universal indicator. Solution X turns orange whereas solution Y turns red. Which of the solution is a stronger acid? 

1.What is the colour change when you add blue litmus to sour substances? 2.Name two synthetic indicators. 3.Which acid is present in lemon juice? 4.Baking soda solution can be used as a remedy for which type of ailments? 5.What is meant by neutralization? 6.Name two natural indicators. 7.What is the colour of methyl orange in acidic solution? 8.What is meant by dilution? 9.What is a universal indicator? 10.On what factors does the strength of a base depend? 11.Give example of common antacid. 12.Write the chemical name & formula of bleaching powder. 13.Name the compound used for removing hardness of water. 14.Which gas is released when an acid reacts with a metal? 15.What are the salts of sulphuric acid called? 16.What is difference between washing soda and soda ash? 17.Give one point difference between an alkali and a base. 18.Name the natural source of acetic acid. 19.When metal carbonates react with acids which gas is produced? 20.What do all acids and bases have in common? 21.Give one example of strong acid and weak acid.

22.What is the chemical name of hardest substance in our body? 23.What is dead burnt plaster ? 24.What is milkiness due to when carbon dioxide gas is passed through lime water? 25.What are olfactory indicators ? 26.On what factors does the strength of an acid depend? 27.What happens when metal oxides react with acids? 28.Nmae four families of salts. 29.What happens when sodium hydrogen carbonate is heated? 30.What is the pH range between which our body works? 31.Why is sulphuric acid called king of chemicals? 32.What are anhydrous and hydrated salts? Explain with examples. 33.What is the difference between a strong base and weak base? Give two example of each. 34.What is deliquescent salt? Give example. 35.Why is tartaric acid added into baking soda to get baking powder? 36.With the help of chemical equation explain how a soda acid fire extinguisher helps in putting out fire. 37.A tarnished copper vessel begins to shine when rubbed with lemon. Why? 38.How is plaster of Paris different chemically different from gypsum? How may they be interconverted? 39.What is efflorescence? Give example. 40.Write any three chemical properties of acids. 41.What happens when chlorine is passed through slaked lime? 42.Define monobasic, dibasic and tribasic acids. 43.Define an acid in terms of ions. 44.What is the role of water in litmus test of an acid? 45. Define base in terms of ions. 46.Differentiate between acids and bases.