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com www.GOALias.blogspot.com www.GOALias ... - fun learning

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<strong>www</strong>.<strong>GOALias</strong>.<strong>blogspot</strong>.<strong>com</strong>When an acidic solution is mixedwith a basic solution, both the solutionsneutralise the effect of each other. Whenan acid solution and a base solution aremixed in suitable amounts, both theacidic nature of the acid and the basicnature of the base are destroyed. Theresulting solution is neither acidic norbasic. Touch the test tube immediatelyafter neutralisation. What do youobserve? In neutralisation reaction, heatis always produced, or evolved. Theevolved heat raises the temperature ofthe reaction mixture.In neutralisation reaction a newsubstance is formed. This is called salt.Salt may be acidic, basic or neutral innature. Thus, neutralisation can bedefined as follows:The reaction between an acid andalt+Watera base is known as neutralisation. Saltand water are produced in this processwith the evolution of heat.Acid+Base Salt+Water(Heat is evolved)The following reaction is an example:Hydrochloric acid (HCl) + Sodiumhydroxide (NaOH)Sodium chloride (NaCl) + Water (H 2O)Boojho added dilute sulphuric acidto lime water. Will the reaction mixturebe<strong>com</strong>e hot or cool?5.4 NEUTRALISATIONSIN EVERYDAYLIFEIndigestionOur stomach contains hydrochloricacid. It helps us to digest food, as youhave learnt in Chapter 2. But toomuch of acid in the stomach causesindigestion. Sometimes indigestionis painful. To relieve indigestion, wetake an antacid such as milk ofmagnesia, which contains magnesiumhydroxide. It neutralises the effect ofexcessive acid.Ant stingThe sting of an ant contains formicacid. When an ant bites, it injectsthe acidic liquid into the skin. Theeffect of the sting can be neutralised byrubbing moist baking soda (sodiumhydrogen carbonate) or calaminesolution, which contains zinccarbonate.Soil treatmentExcessive use of chemical fertilisersmakes the soil acidic. Plants do not growwell when the soil is either too acidic ortoo basic. When the soil is too acidic, itis treated with bases like quick lime(calcium oxide) or slaked lime (calciumhydroxide). If the soil is basic, organicmatter is added to it. Organic matterreleases acids which neutralises thebasic nature of the soil.Factory wastesThe wastes of many factoriescontain acids. If they are allowed toflow into the water bodies, the acidswill kill fish and other organisms.The factory wastes are, therefore,neutralised by adding basicsubstances., BACIDSCIDS, , BASESAND SALTS5555

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