Skip to main content

Quality control interview (Question & Answer) Part-2

Quality control interview

Question.1) What is volumetric or titrimetric analysis.?
Answer: It consists of determination of volume of solution of accurately known concentration required to react completely with the solution or substance to be determined.

Question.2) What is standard solution.?
Answer:  A solution of accurately known strength is known as standard solution, standard solution are usually expressed in terms of molarity or normality.
Type of standard solution:
a) Primary standard
b) Secondary standard

Question.3) What is primary standard solution.?
Answer: Primary standard is a chemical or reagents which has certain properties such as:
  • It is extremely pure
  • Highly stable
  • It is anhydrous
  • It is less hydroscopic
  • Has very high molecular weight
  • Can be weighed easily
  • Should be ready to use and available
  • Should be preferably non toxic
  • Should not be expensive
Question.4) What is extremely pure standard.?
Answer: Primary standard should be extremely pure which means that, it should be a chemical of high grade of purity, preferably 99.98%

Question.5) What is meaning of primary standard stability.?
Answer: It should be highly stable which means it usually does not react easily when kept in its pure form or in other words it should have very low reactivity.

Question.6) What is importance of stability in primary standard.?
Answer: If a reagent reacts easily with atmospheric oxygen or water or changes its property over time then it is unreliable chemical to use as primary standard.

Question.7) What is importance of anhydrous in primary standard.?
Answer: It should be anhydrous which means that it does not contain any water molecule in its molecular structure.
For Example: Magnesium sulphate (MgSO4) is found with formula MgSO4.7H2O. Therefore, to prepare primary standard solution  of MgSO4, anhydrous MgSO4 preferably of analytical grade with purity greater than 99.98% will be required.

Question.8) What is importance of less hydroscopic in primary standard.?
Answer: The chemical preferably should be less hydroscopic that is on opening the container it should not absorb water molecules from atmosphere.

Question.9) What is importance of high molecular weight in primary standard.?
Answer: It should have very high molecular weight to minimize weighing errors.

Question.10) What is use of primary standard.?
Answer: The following use of primary standards.
  • Use of standardize a volumetric solution.
  • They are used for standardization of titration solution.
  • They are used for calibration of secondary standards.
  • Used as reference to determine unknown concentrations or to calibrate an analytical instruments.
Question.11) What is Secondary standard.?
Answer: A secondary standard is a solution which contain exactly known amount of the substance in unit volume of the solution which is determined by titrating against a primary standard.

Question.12) What is properties secondary standard.?
Answer: A secondary standard is a chemical or reagent which has certain properties such as:
  • It has less purity than primary standard.
  • Less stable and more reactive than primary standard.
  • But its solution remains stable a long time.
  • Titrated against primary standard.
Question.13) What is uses of secondary standard.?
Answer: Secondary standard use as following.
  • Secondary standard are commonly used to calibrate analytical equipment and analytical techniques.
  • Used in titration.
Question.14) What is titrate.?
Answer: The substance being titrated taken in conical flask is known as titrate.

Question.15)  What is titrant.?
Answer: The solution of known concentration used in titration which is added from burette are known as titrant.

Question.16) What is end or equivalent point.?
Answer: The point at which reaction between titrate and titrant is just complete indicated by a change in color of indicator is called as endpoint or equivalence point. For example after titration the color of the substance changes due to reaction completion.

Question.17) What is titration.?
Answer: The process of addition of standard solution from burette into the solution of unknown concentration taken in the conical flask is known as titration.

Question.18) What is indicator?.
Answer: It is a complex organic compound which shows clear visual change after the reaction between titrant and titrate is just complete for example Phenolphthalein, Methyl orange, Thymol blue and methyl red.

Question.19) What is titration error.?
Answer: In practice very small difference between theoretical endpoint and actual endpoint usually occurs it is known as titration error example suppose experimental value is 5.10 and actual value is 5.0 then,
                 Experimental value - actual value        (5.1-5.0) 
Error = ------------------------------------------  = -------------- = 0.02
                                Actual value                              5.0
Question.20) What is classification of volumetric analysis.?
Answer: Analysis can be classified as below:
  1. Acid base titration
  2. Redox titration
  3. Complex metric titration 
  4. Precipitation titration
  5. Non eques titration
Question.21) What is acid base titration.?
Answer: It involves the acid-base neutralization reaction in presence of water as solvent these reactions involves combination of hydrogen and hydroxide ion to form water and salt.

Question.22) What is redox titration.?
Answer: These titrations involves the reactions occurring due to transfer of electrons among reacting solutions are either oxidizing or reducing agent.

Question.23) What is complex metric titrations.?
Answer: It includes the titration of a metal ions solution with that of complexing agent to form a weakly dissociated complex substance. It usually involves titration with ethylene-diamine tetra acetic acid which is also called as EDTA.

Question.24) What is precipitation titration.?
Answer: It involves the reaction of ions to yield a precipitate. example chloride ions when combines with silver nitrate it forms silver chloride precipitates titration of silver ion with solution of chloride ion occurs in presence of nitric acid.
                                        Cl- + AgNO3 = AgCl

Question.25) What is non-aqueous titration.?
Answer: It involves reactions between the acid and base in presence of non-equal solvent. For example of organic solvents such as benzene and chloroform. 



Popular posts from this blog

To determine loss on drying (LOD)

To determine loss on drying (LOD) Definition:   Loss on drying compares the weight of product sample before and after drying. The result is the percentage of moisture in a product. % Moisture = (Begging weight-Ending weight) X 100                         -----------------------------------------------                                    Begging weight  Loss on drying determine by two method which is given below: Method (1):   Weigh accurately a dry empty glass Petri dish. Put the sample (about 0.5 to 5 gm as par requirement, Its mean if sample having less wet take 5 g weight. If sample having more wet than take 0.5 g weight ) in dish and weigh. Note down the reading. Distribute the sample in Petri dish by gentle shaking. Place the loaded dish (without cover) in the drying chamber for two hours. Maintain the oven temperature 105 +/- 5 0 C.  After drying is completed, open the drying chamber, cover the dish and allow it to cool at room temp.  Keep it in the desiccator for 15

IR स्पेक्ट्रोस्कोपी और इसका सिद्धांत

IR स्पेक्ट्रोस्कोपी और इसका सिद्धांत  IR स्पेक्ट्रोस्कोपी क्या है और इसका सिद्धांत क्या है? एक अणु या एक रासायनिक यौगिक में यह पता लगाने के लिए कि कौन से कार्यात्मक समूह या समूह मौजूद हैं, हम IR स्पेक्ट्रोस्कोपी तकनीक का उपयोग करते हैं। आईआर स्पेक्ट्रोस्कोपी तकनीक का प्रदर्शन करने के लिए हम विद्युत चुम्बकीय स्पेक्ट्रम की एक विशिष्ट श्रेणी का उपयोग करते हैं जिसे हम IR (इन्फ्रारेड) विकिरण कहते हैं आईआर विकिरण तरंग दैर्ध्य की विभिन्न श्रेणियों से बना है और IR विकिरण के इस अनुप्रयोग को IR स्पेक्ट्रोस्कोपी के रूप में जाना जाता है क्योंकि यह पहचानने के लिए कि सभी कार्यात्मक समूह मौजूद हो सकते हैं हम IR विकिरण का उपयोग करते हैं इसलिए जब हम किसी नमूने पर आईआर विकिरण लागू करते हैं, तो हम इस तकनीक को आईआर स्पेक्ट्रोस्कोपी कहते हैं  अब आइए नजर डालते हैं आईआर स्पेक्ट्रोस्कोपी के सिद्धांत पर   जिस किसी भी नमूना का हम विश्लेषण करना चाहते हैं (नमूना किसी भी रूप में हो सकता है - ठोस, तरल या गैस) हम उसका नमूना तैयार करते हैं और इसे आईआर स्पेक्ट्रोफोटोमीटर में डालते हैं IR स्पेक्ट्रोफोटोमीटर वह उपकरण है

Analytical Method Validation

Analytical Method Validation   The validation is performance, demonstration of any procedure, process, equipment, material, activity or any system performance as expected under given set of condition. In the most basis form, validation is proving that the performance is as intended. When extended to an analytical procedure,depending upon the application, it means that the method works reproducibaly, when carry out by same or different persons, in same or different laboratories, using different reagents, different equipment, etc. The analyst normally tends to assume that if an analytical method or process performs reproducibility in an limited number of experiment, it will continue doing so forever, which is too optimistic to assume. The Benefits:   The biggest   advantage  of method validation is that it builds a degree of confidence, not only for the developer but also to the user. Although the validation exercise may appears costly and time consuming. It is results in expens