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° Types of Errors, , There are two types of errors , ¢ Determinate errors (aslo called systemic errors), , * Indeterminate errors (aslo called non - systemic errors)
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1-Determinate Errors, Determinate errors are also kr, , , , , , , , , , , , , , , , , as systematic errors and ca of these errors are, , known to the analyst. These are usually one sided and by preplanning, , , , y and careful working, can be avoided or kept at minimum. These are errors that have a distinct esteem together, with a sensible assignable cause. In any case, on a basic level these, be measured and represented conveniently, Specific class are, , (a) Personal Errors:, , avoidable mistakes might, The most vital errors having a place with this, , These types of errors are exc lusively caused due to pers, , al mistakes or carelessness of, the analyst. Careful working by the analyst can eliminat, , e these type of errors., , Example: If analyst is wrongly calculating the weight of sod, PrOduce 0.1 N oxalic acid, (6) Instrumental Errors:, , Instrumental errors are due to defect in the equipment; caused, due to faulty and uncalibrated glasswares, apparatus and instruments. These errors can be, , i by using good qudlity apparatus and calibrated glasswares, apparatus and, ments, , , , hydroxide re ed tc, , Ss). These are invariat
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© (c) Reagent Errors: Many reagent:, , These errors are dependent on quality of the individual reagents. Tsicuntty 3, Compounds are not in pure form, they contain impurities. Due to presence ©, occurs., , Example: If Purity of the potassium hydrogen phthalate available in the i, 90% pure and analyst is dissolving 204 g of that compound into 1000 fal: gistilie aad, get the solution of 1 N solution. Then actual normality of the solution will be 0.9 N instec, 1 N; this 0.1 N error occurs due to reagent error., , (d) Additive or Constant Errors:, , Sometimes the value of error is constant in a series determination and is independent, the amount of sample taken for analysis; these are termed as additive errors., , Example: In a titration, 0.1 xtra titrant has to be added to see the colour cha, Clearly at the end point. i.e. énd point error is 0.1 ml. Therefore , if the standard value is 10, the observed value is 10.1 mi, , , , If the sample taken for the titration is doubled, the standard value will be 20 ml, but i, the titration value comes out to be 20.1 ml, , , , It should be noted that the error should remain the same. i.e. 0.1 ml
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It should be noted that the error should remain the same. i.e. 0.1 ml., (e) Proportional Errors:, In this type of error the Magnitude of the error depends upon the sample size., Example: In the titration of 10.0 ml of 0.1 N HCI, 10.0 mi (standard value) of 0.1 N NaOH, , solution should be required. But the NaOH used is impure so the observed value (volume of, titrant) comes out to be 10.2 mi., , The error in the determination is 0.2 mi., It means on doubling the sample the error is also doubled., Hence, the error observed is Proportional error., (f) Errors in Method:, Any error occured durin, category., , Example: If any method involves chemical reaction which takes long time to complete, and the method is carried Out to the next ste, , then error in the method occurs,, BiliNndetarmiancim. , ig the method or selection of wrong method comes under this, , P but the reaction is incomplete at that stage.
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2 Indeterminate/Random Errors, , and reagents. Random erro, , the same ntity is measured several t mes, this difference is called indeterminate err, Examy A ball of 10 g is weighed, weight t nearest Of a gram i.e. whether it, tT we want to know the weight of the, diff ght readings will vary slightly fro, , he ball. ie. 10.0001. 10 00, , AV, 20.0), , Irs are due to causes, , , , e
