Unit 1: Volumetric Analysis
Complete NEB Chemistry 2080 Exercise, Question Answers, MCQs, Numerical, Important Question Note of Class 12 Chemistry Unit 1, Volumetric Analysis.
| Volumetric analysis Course content |
|---|
| 1.1 Define and explain the terms volumetric and gravimetric analysis. |
| 1.2 Express the concentration of solutions in terms of percentage, g/l, molarity, molality, normality, ppm, ppb |
| 1.3 Define and calculate the equivalent weight of (elements, acids, bases, salts, oxidizing and reducing agents). |
| 1.4 Express the concentration of the solution in terms of normality. |
| 1.5 Explain and apply the concept of the law of equivalence in chemical calculation. |
| 1.6 Define and explain primary and secondary standard substances. |
| 1.7 Explain different types of titration and their applications. |
Qualitative Analysis:
Qualitative analysis involves examining the inherent properties of substances to identify and describe their characteristics. This type of analysis focuses on attributes such as color, odor, taste, texture, boiling point, melting point, surface tension, and viscosity. The primary goal is to determine the presence or absence of particular components in a sample without measuring their exact quantities.
Quantitative Analysis:
Quantitative analysis, on the other hand, is concerned with determining the measurable amounts of substances within a sample. This involves calculating parameters such as mass, volume, and the number of moles. The aim is to obtain precise and accurate data about the quantity of the constituents in a sample.
Types of Quantitative Analysis:
- Volumetric Analysis:
- Gravimetric Analysis:
- Instrumental Analysis:
Volumetric analysis is defined as the process of the determination of concentration of unknown solution by finding its volume which will exactly react with a definite volume of another solution of known concentration.
Gravimetric analysis is defined as the process of quantitative determination of an analyte(the ion being analyzed) based on mass of solid.
At first solution of given sample is prepared, treated with suitable reagent to convert into insoluble form which is made pure by washing, dried and weighed. Then the weight of the required substance is calculated with the help of theoretical concept.
Eg. How much SO4– ion is present in a given sample of Na2SO4?
A known amount of the given sample is dissolved in water and the excess amount of BaCl2 is added to the solution so that all SO4– is converted into insoluble BaSO4. The precipitate is washed and made pure, it is then dried and weighed. Let the weight of BaSO4 formed is Y gm.
We know, 233 gm. of BaSO4 contains 96 gm. of SO4– ions.
So, Y gm. of BaSO4 contains $$(96/233) * Y $$ gm. of SO4–ions.
Pre-requirements in volumetric analysis
Equivalent weight (equivalent mass)
It is defined as “the no. of parts by wt. of the substance that combines with or displaces 1.008 parts by wt. of hydrogen, 8 parts by wt. of oxygen or 35.5 parts by wt. of chlorine.”
Equivalent weight is a unit less.
Equivalent weight expressed in gm is called gm. equivalent.
$$No.\,of\, gm. \,eqvt. = given \,wt./eq.\,wt. $$
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