Holiday Homework - Class 10th

	1. AgNO3(aq) + NaCl(aq) → AgCl(s) ↓ + NaNO3(aq) FeS + H2SO4 → FeSO4 + H2S ↑ Consider the above mentioned two chemical equations with two different kinds of arrows ( ↑ and ↓) along with product. What do these two different arrows indicate?	1
	2. Balance the given chemical equation: Al(s) + CuCl2(aq) → AlCl3(aq) + Cu(s)	1
	3. A bud of petunia became reddish purple after first shower of rain. What does it indicate?	1

	4. Write balanced chemical equations for the following reactions: (a) Silver bromide on exposure to sunlight decomposes into silver and bromine. (b) Sodium metal reacts with water to form sodium hydroxide and hydrogen gas.	2
	5. Balance the following chemical equations: (a) BaCl2 + H2SO4 → BaSO4 + HCl (b) Ca(OH)2 + HNO3 → Ca(NO3)2 + H2O (c) Pb(NO3)2 → PbO + NO2 + O2 (d) MnO2 + HCl → MnCl2 + H2O + Cl2	2
	6. A zinc plate was put into a solution of copper sulphate kept in a glass container. It was found that blue colour of the solution gets fader and fader with the passage of time. After a few days when zinc plate was taken out of the solution, a number of holes were observed on it. (a) State the reason for changes observed on the zinc plate. (b) Write the chemical equation for the reaction involved.	2
	7. Consider the following chemical reaction X + Barium chloride →         Y        + Sodium chloride                                        (White ppt) (a) Identify ‘X’ and ‘Y’            (b) The type of reaction	2
	8. Identify the type of reaction from the following equations : (a) CH4 + 2O2 → CO2 + 2H2O (b) Pb(NO3)2 + 2KI → PbI2 + 2KNO3 (c) CaO + H2O → Ca(OH)2 (d) CuSO4 + Zn → ZnSO4 + Cu	2
	9. When the powder of a common metal is heated in an open china dish, its colour turns black. However, when hydrogen is passed over the hot black substance so formed, it regains its original colour. Based on the above information answer the following questions: (a) What type of chemical reaction takes place in each of the two given steps? (b) Name the metal initially taken in the powder form. Write balanced chemical equations for both reactions.	2
	10. Classify each of the following as combination, decomposition, displacement or double displacement reaction: (a) 2KNO3(s) → 2KNO2(s) + O2(g) (b) Zn(s) + 2AgNO3(aq) → Zn(NO3)2 + 2Ag(s) (c) Ni(NO3)2(aq) + 2NaOH → Ni(OH)2↓ + 2NaNO3(aq) (d) N2(g) + 3H2(g) → 2NH3(g)	2
	11. Which among the following changes are exothermic or endothermic in nature? (a) Decomposition of ferrous sulphate (b) Dilution of sulphuric acid (c) Dissolution of sodium hydroxide in water (d) Dissolution of ammonium chloride in water	2
	12. Name the natural source each of the following acids (a) Citric acid (b) Oxalic acid (c) Lactic acid (d) Tartaric acid	2
	13. Given below are the pH values of four different liquids : 7.0, 14.0, 4.0, 2.0 Which of these could be that of (a) lemon juice, (b) distilled water, (c) 1 M sodium hydroxide solution, (d) tomato juice?	2

	14. (a) Write the essential condition for the following reaction to take place: AgBr → 2Ag + Br2 Write one application of this reaction. (b) Complete the following chemical equation of a chemical reaction: 2FeSO4  -->  Fe2O3 + .... + .... (c) What happens when water is added to quick lime. Write chemical equation.	3
	15. Write balanced equations for the following, mentioning the type of reaction involved. (a) Aluminium + Bromine → Aluminium bromide (b) Calcium carbonate → Calcium oxide + Carbon dioxide (c) Silver chloride → Silver + Chlorine	3
	16. State the type of chemical reactions with chemical equations that take place in the following: (a) Magnesium ribbon is burnt in air. (b) Electric current is passed through water. (c) Ammonia and hydrogen chloride gases are mixed.	3
	17. When you have mixed the solutions of lead(II) nitrate and potassium iodide. (a) What was the colour of the precipitate formed and can you name the precipitate ? (b) Write the balanced chemical equation for this reaction. (c) Is this also a double displacement reaction?	3
	18. (a) Classify the following reactions into different types: (i) AgNO3(aq) + NaCl(aq) → AgCl(s) + NaNO3(aq) (ii) CaO(s) + H2O(l) → Ca(OH)2(aq) (iii) 2KClO3(s) 2KCl(aq) + 3O2(g) (b) Which of the above reaction(s) is/are precipitation reaction(s)? Why is a reaction called precipitation reaction?	3
	19. A reddish brown coloured metal, used in electrical wires, when powdered and heated strongly in an open china dish, its colour turns black. When hydrogen gas is passed over this black substance, it regains its original colour. Based on the above information answer the following questions. (a) Name the metal and the black coloured substance formed. (b) Write balanced chemical equations for both the reactions.	3
	20. (a) What is universal indicator ? (b) Write the chemical equation involved in the preparation of sodium hydroxide. Name the process.	3
	21. Answer the following questions: (i) State the colour of phenolphthalein in soap solution. (ii) Name the by-product of chlor-alkali process which is used for the manufacture of bleaching powder. (iii) Name one indicator which specifies the various levels of H+ ion concentration.	3
	22. Name the products formed in each case when (a) hydrochloric acid reacts with caustic soda. (b) granulated zinc reacts with caustic soda. (c) carbon dioxide is passed into lime water.

	23. (a) Write one example for each of decomposion reaction (i) Electricity (ii) Heat (iii) Light (b) Which of the following statements is correct and why copper can displace silver from silver nitrate and silver can displace copper from copper sulphate solution.	5
	24. State reason for the following statements: (a) Tap water conducts electricity whereas distilled water does not. (b) Dry hydrogen chloride gas does not turn blue litmus red whereas dilute hydrochloric acid does. (c) During summer season, a milk man usually adds a very small amount of baking soda to fresh milk. (d) For a dilution of acid, acid is added into water and not water into acid. (e) Ammonia is a base but does not contain hydroxyl group.	5
	25. Equal length of magnesium ribbon are taken in two test tubes ‘A’ and ‘B’. H2SO4 is added to test tube ‘A’ and H2CO3 in the test tube ‘B’ in equal amounts: (a) Identify the test tube shaving vigorous reaction. (b) Give reason to support your answer. (c) Name the gas liberated in both the test tubes. How will you prove its liberation? (d) Write chemical equations for both reactions. (e) Out of the two acids taken above (i) which one will have lower pH value. (ii) lower H+ concentration respectively.	5
	26. (a) Explain why is hydrochloric acid a strong acid and acetic acid, a weak acid. How can it be verified? (b) Explain why aqueous solution of an acid conducts electricity. (c) You have four solutions A, B, C and D. The pH of solution A is 6, B is 9, C is 12 and D is 7, (i) Identify the most acidic and most basic solutions. (ii) Arrange the above four solutions in the increasing order of H+ ion concentration. (iii) State the change in colour of pH paper on dipping in solution C and D.	5
	27. (a) Dry pellets of a base ‘X’ when kept in open absorbs moisture and turns sticky. The compound is also formed by chlor-alkali process. Write chemical name and formula of X. Describe chlor-alkali process with balanced chemical equation. Name the type of reaction that occurs when X is treated with dilute hydrochloric acid. Write the chemical equation. (b) While diluting an acid, why is it recommended that the acid should be added to water and not water to the acid ?	5