{"id":19569,"date":"2018-01-31T10:23:52","date_gmt":"2018-01-31T10:23:52","guid":{"rendered":"https:\/\/cbselibrary.com\/?p=19569"},"modified":"2020-11-25T17:30:29","modified_gmt":"2020-11-25T12:00:29","slug":"cbse-class-10-science-lab-manual-types-reactions","status":"publish","type":"post","link":"https:\/\/cbselibrary.com\/cbse-class-10-science-lab-manual-types-reactions\/","title":{"rendered":"CBSE Class 10 Science Lab Manual – Types of Reactions"},"content":{"rendered":"
EXPERIMENT 3(a)<\/strong><\/span><\/p>\n Aim<\/strong><\/span> Materials Required<\/strong><\/span> Theory<\/strong><\/span> Procedure<\/strong><\/span><\/p>\n Observation<\/strong><\/span> Inference<\/strong><\/span> Result<\/strong><\/span> Precautions<\/strong><\/span><\/p>\n Viva – Voce<\/strong><\/span><\/p>\n Question 1.<\/span><\/strong> Question 2.<\/span><\/strong> Question 3.<\/span><\/strong> Question 4.<\/span><\/strong> Question 5.<\/span><\/strong> Question 6.<\/span><\/strong> Question 7.<\/span><\/strong> Question 8.<\/span><\/strong> Question 9.<\/span><\/strong> Question 10.<\/span><\/strong> Question 11.<\/span><\/strong> Question 12.<\/span><\/strong> Question 13.<\/span><\/strong> Question 14.<\/span><\/strong> Question 15.<\/span><\/strong> Question 16.<\/span><\/strong> Question 17.<\/span><\/strong> EXPERIMENT 3(b)<\/strong><\/span><\/p>\n Materials Required<\/strong><\/span> Theory<\/strong><\/span> Procedure<\/strong><\/span><\/p>\n Observation<\/strong><\/span><\/p>\n Inference<\/strong><\/span><\/p>\n Result<\/strong><\/span> Precautions<\/strong><\/span><\/p>\n Viva – Voce<\/strong><\/span><\/p>\n Question 1.<\/span><\/strong> Question 2.<\/span><\/strong> Question 3.<\/span><\/strong> Question 4.<\/span><\/strong> Question 5.<\/span><\/strong> Question 6.<\/span><\/strong> Question 7.<\/span><\/strong>
\nTo perform and observe the action of water on quicklime, action of heat on ferrous sulphate crystals, reaction of iron nails kept in copper sulphate solution, reaction between sodium sulphate and barium chloride solutions and classify the reaction.<\/p>\n
\nCalcium oxide (quicklime), distilled water, borosil beaker, test tube, glass rod, dropper, red and blue litmus paper strips.<\/p>\n
\nWhen calcium oxide (quicklime) is dissolved in water, it forms calcium hydroxide (slaked lime). The reaction is highly exothermic, i.e. a lot of heat is produced during the reaction.
\nThis reaction may be represented in the form of a chemical reaction as follows:
\n
\nNote Calcium hydroxide is basic in nature.
\nTherefore, it turns moist red litmus paper blue. If we pass CO2<\/sub> through clear calcium hydroxide solution (lime water), it turns milky due to the formation of a white precipitate (insoluble calcium carbonate).
\n
\nIn reaction (i), two compounds-quicklime and water combine to give a single product slaked lime. So, this is an example of combination reaction. Hence, it may be stated that when two or more substances react together to form a single product, is called a combination reaction.
\nAlso, it has been observed that a large amount of heat is evolved alongwith the formation of products. Such type of reactions which are accompanied by the evolution of heat, are called exothermic reactions.<\/p>\n\n
\n<\/li>\n
\n<\/li>\n<\/ol>\n
\nThe hissing sound is produced and solution becomes hot. The heat is evolved during the reaction which raises the temperature of the reaction mixture. On putting a few drops of the solution on red and blue litmus paper, it is observed that only red litmus paper turns blue, no changes occur in blue litmus paper.<\/p>\n
\nIn this reaction, quicklime (CaO) and water (H2<\/sub>O) combine to give a single product slaked lime [Ca(OH)2<\/sub> ].
\nCaO(s) + H2<\/sub>O (l) ——–> Ca(OH)2<\/sub> (aq) + Heat
\nIt is a combination reaction and calcium hydroxide [Ca(OH)2<\/sub> ] is basic in nature.
\nAs heat is evolved, the reaction is exothermic.<\/p>\n
\nThe reaction between quicklime and water to form slaked lime is a combination reaction as well as exothermic reaction.<\/p>\n\n
\nWhat is combination reaction?
\nAnswer:<\/strong><\/span>
\nA reaction in which two or more substances combine to form a single product (compound) is called a combination reaction.<\/p>\n
\nWhat is calcium oxide commonly called?
\nAnswer:<\/strong><\/span>
\nCalcium oxide (CaO) commonly known as quicklime.<\/p>\n
\nWhen slaked lime is brought in contact with red litmus paper, what do you observe?
\nAnswer:<\/strong><\/span>
\nWe observe that red litmus paper turns blue. From this, we can conclude that slaked lime is basic in nature.<\/p>\n
\nA small amount of quicklime is taken in a beaker. Water is added slowly to the beaker. What observation would you note down?
\nAnswer:<\/strong><\/span>
\nWhen water is added slowly in a quicklime, hissing sound is produced and the solution becomes hot.<\/p>\n
\nName the reaction between calcium oxide and water.
\nAnswer:<\/strong><\/span>
\nThe reaction between calcium oxide and water is known as combination reaction.<\/p>\n
\nWhy should we not touch iron container in which CaO reacts with H2<\/sub>O?
\nAnswer:<\/strong><\/span>
\nWe should not touch iron container in which CaO reacts with H20 because iron container will be very hot as the reaction is exothermic.<\/p>\n
\nWrite the product formed when quicklime reacts with water.
\nAnswer:<\/strong><\/span>
\nQuicklime reacts with water to give calcium hydroxide Ca(OH)2<\/sub>, ie. slaked lime.
\nCaO+ H2<\/sub>O ——–> Ca(OH)2<\/sub><\/p>\n
\nWhat is the effect of temperature on the solubility of calcium hydroxide?
\nAnswer:<\/strong><\/span>
\nSolubility of calcium hydroxide or slaked lime decreases with increase in temperature.<\/p>\n
\nIs the reaction between quicklime and water exothermic or endothermic?
\nAnswer:<\/strong><\/span>
\nAs heat energy is released during the reaction, therefore it is an exothermic reaction.<\/p>\n
\nName the chemical formula and chemical name of slaked lime.
\nAnswer:<\/strong><\/span>
\nChemical formula of slaked lime \u2014 Ca(OH)2<\/sub>
\nChemical name of slaked lime \u2014 Calcium hydroxide<\/p>\n
\nMost of the combination reactions are exothermic in nature. Give reason.
\nAnswer:<\/strong><\/span>
\nMost of the combination reactions are accompanied by liberation of heat energy. This is known as exothermicity. For example, when natural gas burns in the oxygen of air, it forms carbon dioxide and water vapour. A large amount of heat is also produced.
\n<\/p>\n
\nGive an example of a combination reaction.
\nAnswer:<\/strong><\/span>
\nWhen magnesium ribbon burns in air, it forms magnesium oxide. This is an example of combination reaction.
\n<\/p>\n
\nHow is lime water prepared?
\nAnswer:<\/strong><\/span>
\nMix calcium oxide with water, shake the mixture well and leave it to stand for a while. Collect the clean solution on top. This is lime water.<\/p>\n
\nWhat is the suspension of slaked lime in water commonly called?
\nAnswer:<\/strong><\/span>
\nThe suspension of slaked lime in water is commonly called milk of lime.<\/p>\n
\nWhy lime water turns milky when CO2<\/sub> gas is passed through a test tube containing lime water?
\nAnswer:<\/strong><\/span>
\nLime water turns milky due to the formation of insoluble precipitate of calcium carbonate (CaCO3<\/sub>).<\/p>\n
\nAvinav takes 2 mL of clear liquid from the mixture of quicklime with water and then he breath out in it. What would he observed?
\nAnswer:<\/strong><\/span>
\nThe filtrate turns milky.<\/p>\n
\nOut of CuO, Na2<\/sub>O, CaO and P2<\/sub>O5<\/sub>, in which oxide solution, lime water is formed when water is mixed?
\nAnswer:<\/strong><\/span>
\nWhen water is mixed with CaO, lime water is formed<\/p>\n
\nFerrous sulphate crystals (2g), boiling tube, test tube holder, safety glass (goggle), Bunsen burner, blue and red litmus paper strips.<\/p>\n
\nThe ferrous sulphate crystals are actually ferrous sulphate heptahydrate (FeSO4<\/sub>.7H2<\/sub>O). They contain seven molecules of water of crystallisation. These crystals are green in colour.
\nHeating of Ferrous Sulphate Crystals<\/strong>
\nWhen the green coloured ferrous sulphate heptahydrate crystals (FeSO4<\/sub>.7H2<\/sub>O) are heated, they first lose seven molecules of water of crystallisation to form anhydrous ferrous sulphate (FeSO4<\/sub> ) which is white in colour.
\nWhen this anhydrous ferrous sulphate is heated, it decomposes to give ferric oxide, sulphur dioxide and sulphur trioxide.
\nThe reactions may be represented as:
\n
\nIn this reaction, one substance FeSO4<\/sub>(s) is splitting up into three substances Fe2<\/sub>O3<\/sub>(s), SO2<\/sub>(g), SO3<\/sub>(g) because it takes place due to heat.
\nSo, this is a decomposition reaction. It is actually a thermal decomposition reaction.
\nOn combining Eqs. (i) and (ii), we can write the reaction as:
\n<\/p>\n\n
\n<\/li>\n
\n<\/li>\n
\n<\/li>\n\n
\n
\nHeating of ferrous sulphate crystals is a decomposition reaction<\/strong> and it decomposes to give ferric oxide (Fe2<\/sub>O3<\/sub>), sulphur dioxide (SO2<\/sub>) and sulphur trioxide (SO3<\/sub>).<\/p>\n\n
\nWhat is decomposition reaction?
\nAnswer:<\/strong><\/span>
\nWhen a compound decomposes to give two or more simpler substances, it is a decomposition reaction. When lead nitrate Is heated, it decomposes as shown below:
\n<\/p>\n
\nWrite the formula of ferrous sulphate crystals.
\nAnswer:<\/strong><\/span>
\nFeSO4<\/sub>.7H2<\/sub>O<\/p>\n
\nWhat is the common name of ferrous sulphate crystals?
\nAnswer:<\/strong><\/span>
\nThe common name of ferrous sulphate crystals are green vitriol<\/p>\n
\nWhen FeSO4<\/sub> crystals are strongly heated, it given off some gases. Name these gases.
\nAnswer:<\/strong><\/span>
\nThese gases are sulphur dioxide (SO2<\/sub>) and sulphur trioxide (SO3<\/sub>), which have suffocating smell like burning sulphur.<\/p>\n
\nThe heating of ferrous sulphate (FeSO4<\/sub>.7H2<\/sub>O) is an example of which type of reaction?
\nAnswer:<\/strong><\/span>
\nThe heating of FeSO4<\/sub>. 7H2<\/sub>O is an example of decomposition reaction.<\/p>\n
\nWhat happens when crystals of ferrous sulphate are heated?
\nAnswer:<\/strong><\/span>
\nFerrous sulphate crystals (FeSO4<\/sub>.7H2<\/sub>O) lose water when heated and the colour of crystals changes. It then decomposes to ferric oxide (Fe2<\/sub>O3<\/sub>), sulphur dioxide (SO2<\/sub>) and sulphur trioxide (SO3<\/sub>). Fe2<\/sub>O3<\/sub> is solid while SO2<\/sub> and SO3<\/sub> are gases.
\n<\/p>\n
\nOn heating ferrous sulphate crystals, two gases are evolved. Which gas produces fumes of sulphuric acid when it comes in contact with moist air?
\nAnswer:<\/strong><\/span>