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  Chemical Kinetics   The study of the rate of chemical reaction, factors affecting rate of chemical reaction and mechanism of chemical reaction is called Chemical Kinetics. Types of Chemical Reactions Based on Reaction Rate There are three types of chemical reactions on the basis of the reaction rate. Instantaneous Reactions These are the reactions which are completed at once e.g. reactions between aqueous solutions of AgNO 3 and NaCl to form a white precipitate of AgCl, decolourization of acidified KMnO 4 with FeSO 4 solution. Moderate Reactions These are the reactions which proceed at a moderate speed. The accurate measurement of the rates of reaction is possible e.g. hydrolysis of ethyl acetate to form ethyl alcohol and acetic acid, decomposition of hydrogen iodide into hydrogen and iodine. Slow Reaction These are the reactions which take long time to complete, e.g. rusting of iron, fixation of atmospheric nitrogen.   Rate of Reaction The ...
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alkaline phosphatase isoenzymes?

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  Isoenzymes It was a tremendous step forward for research on the biochemistry of differentiation when it was discovered that some of the universally distributed enzymes have different molecular forms with a variety of subunits, characteristic of different tissues. Market and Møller (1959) were the first to make a survey of the patterns of nonspecific esterases in developing tissues of vertebrates and to recognize tissue-specific differences both in the activities of the different enzymes and in their polypeptide subunits. A general survey of isoenzyme changes during development in amphibians was carried out by Chen (1968). He compared proteins extracted from embryonic, larval, and adult stages of three species,  Bombina variegata, Rana temporaria,  and  Triturus alpestris,  and identified subunits of lactate dehydrogenase (LDH), malate dehydrogenase (MDH), alcoho...
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What is Pauly's Test for amino acid?

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  Pauly’s test is a biochemical test for the detection of tyrosine and histidine where the reagent couples with amines, phenols, and imidazole groups. The test was discovered by and is named after the German Chemist Hermann Pauly. Pauly’s test is a specific test for proteins containing tyrosine and histidine as the reagent undergoes diazotization with aromatic groups. The reaction is performed under cold conditions as the diazonium compound can only form at cold temperatures. The test is a specific test for proteins, which is performed for further differentiation between amino acids and proteins. Principle                    ❖   Pauly’s test is based on the principle of coupling between the amino acids and the diazonium ion formed in the reagent. The pauly’s reagent consists of sulphanilic acid dissolved in concentrated hydrochloric acid. The sulfanilic acid undergoes diazotization in the presence of sodium nitrate and hydr...
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How to Find out the Rheochor value of the given organic liquid?

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  Experiment:   Find out the Rheochor value of the given organic liquid. Molar mass (or Molecular weight) of the given liquid is 46.   Theory: Newton Friend showed that if molecular volume (or molar volume) of a liquid be multiplied by the eighth root of the coefficient of viscosity, it leads to a constant called rheochor., denoted by r.                           R = (M/D ) h 1/8 D is density of the liquid and M its molar volume Rheochor may be regarded as the molar volume of a liquid at the temperature at which its viscosity is unit.   Apparatus:   Ostwald’s viscometer, stop-watch, specific gravity bottle, rubber tube, screw type pinch cock, iron stand etc.   Procedure:   ·          Take an Ostwald’s viscometer and fix it in a stand in upright position. · ...
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How to Determine the Viscosity of a liquid at room temperature by viscometer?

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  Experiment: Determine the Viscosity of a liquid at room temperature by viscometer.   Theory:   Viscosity is a characteristic property of all fluids. The internal resistance of a liquid to its flow is called viscosity. Viscosity can be explained if a liquid is considered to consist of concentric layers which slide past one another when a liquid flows. Resistance to flow is regarded as an internal friction between the different layers of a liquid. So viscosity is a property of liquids by virtue of which it tends to oppose the relative motion between different layers of the liquid. Viscosity of a liquid is expressed in terms of Coefficient of Viscosity. Coefficient of Viscosity is defined as the force (in dynes) per unit area (one square centimeter) required to maintain unit difference of velocity between two parallel layers in the liquid, unit distance (one centimeter) apart. It is denoted by h (eta).   Units of Viscosity (Coefficient of Viscosi...
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