valumetric analysis & gravimetric analysis Imp MCQs Question with Answeralumetric analysis & gravimetric analysis Imp MCQs Question with Answer.pptx

valumetric analysis & gravimetric analysis Imp MCQs Question with Answer
Prepared By GULAM MUHEYUDDEEN
ASSISTANT PROFESSOR
Department Of Pharmaceutical Chemistry
Jahangeerabad Institute Of Technology (Faculty Of Pharmacy) BARABANKI

1. TOPICS Introduction principle application of all titration Fundamental of volumetric analysis Acid base titration Non aqueous titration Precipitation titration Complexometric titration Redox titration Gravimetric analysis Masking and demasking agent Types of solvent Prepared By GULAM MUHEYUDDEEN ASSISTANT PROFESSOR Department Of Pharmaceutical Chemistry Jahangeerabad Institute Of Technology (Faculty Of Pharmacy) BARABANKI

2. 16. The stage during titration at which the reaction is just completed is called as …… Equivalent point Neutralization point End point Critical point

3. 16. The stage during titration at which the reaction is just completed is called as …… Equivalent point Neutralization point End point Critical point

4. Neutralization point In chemistry,  neutralization  or  neutralisation  (see  spelling differences ) is a  chemical reaction  in which  acid  and a  base  react with an equivalent quantity of each other. In a reaction in water, neutralization results in there being no excess of hydrogen or hydroxide ions present in the solution. The  pH  of the neutralized solution depends on the acid strength of the reactants . What is an Endpoint? The endpoint in titration refers to the point at which the indicator changes colour in the colourimetric titration. For example, in complexometric titration, if Eriochrome Black T is used as an indicator, then at the endpoint, colour changes from wine red to blue.   What is the Equivalence Point?  The equivalence point is also known as a stoichiometric point in the titration. During titration, the point at which the added titrant is chemically equivalent to the analyte in the sample is called the equivalence point. 

5. 17. KMnO4 is used as strong ………………..and…………………in redox titration. Oxidizing agent, self indicator Oxidizing agent, not indicator Reducing agent, self indicator Reducing agent, not indicator

6. 17. KMnO4 is used as strong ………………..and…………………in redox titration. Oxidizing agent, self indicator Oxidizing agent, not indicator Reducing agent, self indicator Reducing agent, not indicator

7. 18. Which of the following is not used in redox titration? Phenolphthalein Diphenylamine 1,10 Phenanthroline Potassium permanganate

8. 18. Which of the following is not used in redox titration? Phenolphthalein Diphenylamine 1,10 Phenanthroline Potassium permanganate

9. 19. Which of the following method is not used to determine end point in precipitation titration. Addition of potassium permanganate Formation of colored permanganate Formation of soluble colored compound Use of adsorption indicator

10. 19. Which of the following method is not used to determine end point in precipitation titration. Addition of potassium permanganate Formation of colored permanganate Formation of soluble colored compound Use of adsorption indicator

11. What is Precipitation Titration? Precipitation titration is a type of titration which involves the formation of precipitate during the titration technique. In precipitation titration, the titrant reacts with the analyte and forms an insoluble substance called a precipitate. It continues till the last amount of analyte is consumed. It is used to determine chloride by using silver ions.  Precipitation Titration Example  Determination of concentration of chloride ions in a solution by using silver ions of a known solution is an example of precipitation titration. Reactions involved are as follows –    AgNO 3 +NaCl AgCl + NaNO 3 (in a solution of NaCl ) (White ppt ) Argentometric Titration  It is a type of precipitation titration which involves the use of silver ions. The symbol of silver is Ag which is taken from its Latin name Argentum. So, the word argentometric is also taken from the Latin word Argentum.    Methods of Argentometric Titration Volhard’s Method  Fajan’s Method  Mohr’s Method 

12. Applications of Precipitation Titration  It is used for the determination of halide ions in the solution.  It is used to measure salt content in food, beverages and water.  It is used for Sulphur , thiocyanate , dichromate etc.  Many drugs such as carbromal , KCl infusion, NaCl infusion etc. can be analysed by precipitation titration.  It can be used for the determination of concentration of anions in the analyte .

13. 20. What volume of 0.5 N HCl are required to neutralize 25 ml of 0.1 N NaOH solution? 25ml 5ml 10ml 12.5ml

14. 20. What volume of 0.5 N HCl are required to neutralize 25 ml of 0.1 N NaOH solution? 25ml 5ml 10ml 12.5ml

15. 21. In precipitation titration, titration between silver nitrate and thiocynate ion is done by……………… Fajan method Volhard method Mohr’s method None of the above

16. 21. In precipitation titration, titration between silver nitrate and thiocynate ion is done by……………… Fajan method Volhard method Mohr’s method None of the above

17. Volhard’s Method  German Chemist- Jacob Volhard This method was first given by German Chemist Jacob Volhard in 1874. This method involves the determination of halide (F, Cl , Br, I) ions, anions like phosphate, chromate in acidic medium by using silver ions. This titration must be performed in an acidic medium otherwise iron ion get precipitated as hydrated oxide. Iron ions are used as indicators in Volhard’s method. In this method, 1 st analyte (halide ion solution or any other anionic solution) is titrated with a measured excess of AgNO 3 .  Reaction – If the analyte contains chloride anions. The reaction will be as follows -  Cl - + Ag + AgCl + Ag + (in excess ) Now the unreacted or in excess silver ions are titrated with a standard solution of KSCN using iron ion (Fe +3 ) as an indicator which gives red color in the end point.  Reaction – The reaction can be shown as follows-  Ag + + SCN - AgSCN   Now as the thiocyanate ion will be in excess in the titration mixture, red colour appears which is due to the formation of the FeSCN (II) compound.  Reaction – Reaction involved can be shown as follows –  Fe +3 + SCN - FeSCN +2                          (Red colored compound ) It is an indirect method of precipitation.   

18. 22. In Mohr's method detection of end point is……………… Insoluble compound Soluble compound Colorless precipitate Colour precipitate

19. 22. In Mohr's method detection of end point is……………… Insoluble compound Soluble compound Colorless precipitate Colour precipitate

20. Mohr’s Method  Karl Friedrich Mohr This method was given by Karl Friedrich Mohr, a German Chemist. That’s why this method is called Mohr’s method. It’s a direct titration method. In this method silver nitrate is used as titrant and chloride ion solution as analyte . Potassium chromate is used as an indicator. At the end point, when all chloride ions are consumed by silver ions, reddish brown colored precipitate is formed by reaction of silver ions and chromate ions.  Reaction- Reaction involved can be written as follows –    AgNO 3      + Cl - AgCl +NO 3 -    (in solution of NaCl ) (White ppt )   At the end point –    2Ag + + CrO 4 -2 Ag 2 CrO 4                              (Reddish Brown ppt )

21. 23. Which of the following is an examples of adsorption indicators? Phenolphthalein Methyl red Ninhydrin Eosin

22. 23. Which of the following is an examples of adsorption indicators? Phenolphthalein Methyl red Ninhydrin Eosin

23. The phenomenon of adsorption is used to detect the endpoints of precipitation titrations. In such titrations, dyestuffs like eosin, fluorescein, alizarin red etc , are used as adsorption indicators. At the endpoint of the titration anions of indicator adsorb on precipitate and colour change of the precipitate takes place. When a known volume of KBr (in a conical flask) is titrated against AgNO 3  (in burette) using eosin as adsorption indicator, AgBr a white precipitate is formed. AgNO 3  + KBr   →   Ag + Br –  +  KNO 3 There is no colour change of the precipitate as long as Br –  ions are present in the solution. Before endpoint AgBr precipitate is in contact with unreacted KBr and therefore it will adsorb Br –  ions and negatively charged ( AgBr )Br –  are formed. The negatively charged precipitate will repel anions of eosin which are pink in colour. Colour of precipitate remains unchanged. When all Br –  ions are consumed i.e. entire KBr is converted into AgBr , at this stage, an excess drop of AgNO 3  results into adsorption of Ag +  ions and ( AgBr ) Ag +  are formed. These particles immediately adsorb the coloured anions of the indicator eosin and colour of the precipitate changes to pink.  This is the end of the titration.

24. 24. Complexometric titration is useful for the determination of……………… Halides Acid and base Non-metal ions Metal ions

25. 24. Complexometric titration is useful for the determination of……………… Halides Acid and base Non-metal ions Metal ions

26. An introduction to Complexometric Titration Complexometric titration is a volumetric analysis where the endpoint of the analysis or titration is identified by the formation of a coloured complex. It is mainly useful for the determination of a mixture of different metal ions in solution . It is also known as chelatometry Complexometric titrations are used for the determination of the concentration of metal ions in the solution . Complexometric Indicator Complexometric indicators are those indicators that are used in complexometric titrations. These indicators undergo a definite colour change in presence of specific metal ions. These indicators are also known as pM indicators or metallochromic indicators. These indicators are organic molecules that are soluble in water. Calcein , curcumin , Eriochrome Black T, fast sulphon   black, hematoxylin , etc. are some examples of complexometric indicators . Applications of Complexometric Titrations Complexometric titration is used for the estimation of the amount of total hardness in water.  It is widely used in the pharmaceutical industry to determine the metal concentration in drugs.  Titanium dioxide is used in many cosmetic products. This can be analysed by complexometric titration.  It is used to analyse urine samples. It is widely used in analytical chemistry. 

27. 25. In complexometric titration which buffer solution is used? 10 9.2 7 4.2

28. 25. In complexometric titration which buffer solution is used? 10 9.2 7 4.2

29. Complexometric titration: the titration which involves the formation of complexes is known as Complexometric titration. EDTA is commonly used a complexing agent which make a complex with metal ions. The Buffer solution is used to resist the change in pH. Because all reactions between metal ions and EDTA are pH dependent. Change in pH may lead to the improper reaction between Metal ion and EDTA . EDTA: EDTA ( Ethylenediaminetetraacetic acid) is a complexometric indicator made up of two amino groups and four Lewis bases (carboxyl groups). Because of its ability to signify six pairs of lonely electrons owing to the creation of covalent bonds, Edta is a hexadentate ligand. Buffer: In EDTA titration, pH 10 buffer is employed because Y 4-  is prevalent in EDTA, and Y4- is needed to react with the metal ions present in the titration solution. A pH 10 buffer can be used to achieve this. Hence, pH 10 buffer is used in EDTA titration.

30. 26. ……………………is a titrimetric method which involves the formation of precipitates during the experiments of titration. Complexometric Gravimetric Precipitation None of them

31. 26. ……………………is a titrimetric method which involves the formation of precipitates during the experiments of titration. Complexometric Gravimetric Precipitation None of them

32. 27. ……………….titration is a form of volumetric titration in which the formation of a colored complex is used to indicate the end point of titration. Gravimetric Volumetric Complexometric Precipitation

33. 27. ……………….titration is a form of volumetric titration in which the formation of a colored complex is used to indicate the end point of titration. Gravimetric Volumetric Complexometric Precipitation

34. 28. ………………….. method are quantitative methods that are based on measuring the mass of a pure compound to which the Analyte is chemically related. Gravimetric Volumetric Precipitation None of them

35. 28. ………………….. method are quantitative methods that are based on measuring the mass of a pure compound to which the Analyte is chemically related. Gravimetric Volumetric Precipitation None of them

36. Gravimetric Analysis: Gravimetric analysis is one of the commonly used quantitative methods in analytical chemistry, the other being the volumetric method. In gravimetric analysis, the amount of an ion present in an analyte is estimated based on the parameter of mass . Types of Gravimetric Analysis: There are four types of gravimetric analysis based on the method of separation employed in the process. They are: 1. Precipitation Method: An analytical method called precipitation gravimetry uses a precipitation reaction to separate ions from a solution. Precipitant or precipitating agent refers to the substance that is added to produce precipitation. Filtration can be used to separate the solid precipitate from the liquid components, after which the mass of the solid and the balanced chemical equation can be used to determine the quantity or concentration of ionic compounds in the solution. 2. Volatilization Method: In volatilization gravimetry , the sample is heated or chemically broken down to separate the components of our mixture. Any volatile compounds are separated out by the heating or chemical decomposition, which causes a change in mass that can be measured. 3. Electrogravimetry Method: The principle of electrogravimetry is similar to  electroplating;  here, the metal ions are isolated from the solution by depositing on the surface of the electrode. 4. Thermogravimetric Method: In this the mass of the sample is determined based on the observed changes in chemical and physical properties over a period of time of varying temperature.

37. 29. In ………………………….method potassium chromate is used as an indicator which produce red colored silver chromate at the end point when all the chloride ions have reacted. Fajan’s Volhard’s Mohr’s None of them

38. 29. In ………………………….method potassium chromate is used as an indicator which produce red colored silver chromate at the end point when all the chloride ions have reacted. Fajan’s Volhard’s Mohr’s None of them

39. 30. In …………………method soluble colored compound forms at the end point. Mohr's Volhard’s Fajan’s None of them

40. 30. In …………………method soluble colored compound forms at the end point. Mohr's Volhard’s Mohr’s None of them

41. 31. ……………………….. Is similar to acid base titration and involves adding the standard chelon solution to the metal ion solution till the end point is attained. Back titration Replacement titration Indirect titration Direct titration

42. 31. ……………………….. Is similar to acid base titration and involves adding the standard chelon solution to the metal ion solution till the end point is attained. Back titration Replacement titration Indirect titration Direct titration

43. 32. In ……………….method the metal to be analyzed quantitavely displaces the metal from the complex. Replacement titration Back titration Indirect titration Direct titration

44. 32. In ……………….method the metal to be analyzed quantitatively displaces the metal from the complex. Replacement titration Back titration Indirect titration Direct titration

45. 33. A …………………..reagents enables the masked substance to enter into a particular reaction. Chelate compound Masking reagents Demasking reagents None of them

46. 33. A …………………..reagents enables the masked substance to enter into a particular reaction. Chelate compound Masking reagents Demasking reagents None of them

47. Method of masking & demasking Masking by precipitation Masking by complex formation Dimercaprol Ammonium fluoride Ascorbic acid Potassium cyanide Potassium iodide Tiron Triethanolamine pH control method use of selective metal indicator classical sepration Solvent extraction Removal of anions Kinetic masking

48. 34. Measuring the volume of substance that combines with the first known preparation is known as……………. Precipitation titration Complexometric titration Volumetric titration Redox titration

49. 34. Measuring the volume of substance that combines with the first known preparation is known as……………. Precipitation titration Complexometric titration Volumetric titration Redox titration

50. 35. The first methos of volumetric analysis was derived and found by freach chemist………………. Volhdhard Mular Fazan Jean-Baptiste Andre

51. 35. The first methods of volumetric analysis was derived and found by freanch chemist………………. Volhdhard Mular Fazan Jean-Baptiste Andre

52. 36. An ………....... Titration is a method of quantitative analysis for determining the concentration of an acid or base by exactly neutralizing it with a standard solution of base or acid. Acid- Base titration Non aqueous titration Redox titration None of the above

53. 36. An ………....... Titration is a method of quantitative analysis for determining the concentration of an acid or base by exactly neutralizing it with a standard solution of base or acid. Acid- Base titration Non aqueous titration Redox titration None of the above

54. 37. A …………….is a titration without osomalyte being present, only the solvent is used to analyte solution and titration carried out. Back titration Blank titration Acid base titration None of the above

55. 37. A …………….is a titration without osomalyte being present, only the solvent is used to analyte solution and titration carried out. Back titration Blank titration Acid base titration None of the above

56. 38. The undissociated indicator acid on a base has a colour different from its ion. This theory is………. Theory. Resonant Mular Fazon Ostwald

57. 38. The undissociated indicator acid on a base has a colour different from its ion. This theory is………. Theory. Resonant Mular Fazon Ostwald

58. 39. The process where a solution of known strength is added to a certain volume of a treated sample containing an indicator is called as …………….. Titrant Titrand Titration curve Titration

59. 39. The process where a solution of known strength is added to a certain volume of a treated sample containing an indicator is called as …………….. Titrant Titrand Titration curve Titration

60. 40. An acid is any molecule or ion that can donate a proton (H+) And a base is any molecules or ion that can accept a proton: this is called ………………theory. Fazan’s Bronwsted Lowry’s Mular’s Resonant’s

61. 40. An acid is any molecule or ion that can donate a proton (H+) And a base is any molecules or ion that can accept a proton: this is called ………………theory. Fazan’s Bronwsted Lowry’s Mular’s Resonant’s

62. 41. Sodium hydroxide is a…………. Weak acid Weak base Strong acid Strong base

63. 41. Sodium hydroxide is a…………. Weak acid Weak base Strong acid Strong base

64. 41. Hydrofloric acid (HF) is a…………. Weak acid Weak base Strong acid Strong base

65. 41. Hydrofloric acid (HF) is a…………. Weak acid Weak base Strong acid Strong base

66. 42. Which of the following is a mixed indicator? Acetic acid Hydrochloric acid Perchloric acid Litmus

67. 42. Which of the following is a mixed indicator? Acetic acid Hydrochloric acid Perchloric acid Litmus

68. 43. Liquid ammonia is an example of ………… Protophillic solvent Perchloric acid Amphiprotic solvent Protogenic solvent

69. 43. Liquid ammonia is an example of ………… Protophillic solvent Perchloric acid Amphiprotic solvent Protogenic solvent

70. 44. Solvent are considered chemically neutral or inert under specific condition. Photophilic Protogenic Amphiprotic Aprotic

71. 44. Solvent are considered chemically neutral or inert under specific condition. Photophilic Protogenic Amphiprotic Aprotic

72. 45. An ……………agent is a chemical species that causes the other reactant in a redox reaction. Primary Oxidation number Oxidizing agent End point

73. 45. An ……………agent is a chemical species that causes the other reactant in a redox reaction. Primary Oxidation number Oxidizing agent End point

74. 46. Iodine, potassium, iodate, potassium bromate etc. are used as ……………. End point Primary standard Reducing agent Redox system

75. 46. Iodine, potassium, iodate, potassium bromate etc. are used as ……………. End point Primary standard Reducing agent Redox system

76. 47. ………is a titration process in which the bromination of a chemical indicator is observed. Bromatometry Permangnometry Dichromatometry Cerimetry

77. 47. ………is a titration process in which the bromination of a chemical indicator is observed. Bromatometry Permangnometry Dichromatometry Cerimetry

78. 48. ……………….is added in prepration of ceric ammonium sulphate. Oxalate acid Nitric acid Sulphuric acid Iodine

79. 48. ……………….is added in prepration of ceric ammonium sulphate. Oxalate acid Nitric acid Sulphuric acid Iodine

80. 49. Wather H erman Nernst was a ………………. Chemist. American British French German

81. 50. Loss of electron from an electrode if explained as …………… Oxidation potential Reduction potential Cerimetry None of them

82. 50. Loss of electron from an electrode if explained as …………… Oxidation potential Reduction potential Cerimetry None of them

83. 49. Wather H erman Nernst was a ………………. Chemist. American British French German

84. 49. Wather H erman Nernst was a ………………. Chemist. American British French German