Preparation of Stock Solution - Biochemistry Lab (BIT12060), Btech Biotechnology - Adamas University

ADAMAS UNIVERSITY,

SCHOOL OF LIFE SCIENCE & BIOTECHNOLOGY,

DEPT. OF BIOTECHNOLOGY

SUB: BIOCHEMISTRY LAB

CODE: BIT12060

B.Tech BIOTECHNOLOGY, Semester III

Experiment Number - 01

How to prepare a stock solution

Objectives:

                                    • To learn handling the digital balance
                                    • To learn how to prepare a solution

INTRODUCTION: 

A Stock solution is prepared by weighing out an appropriate portion of a pure solid or by measuring out an appropriate volume of a pure liquid, placing it in a suitable flask, and diluting to a known volume. Exactly how one measure’s the reagent depends on the desired concentration unit. 

PRINCIPLE: 

Solutions are often prepared by diluting a more concentrated stock solution. A known volume of the stock solution is transferred to a new container and brought to a new volume. Since the total amount of solute is the same before and after dilution, we know that 

Co×Vo=Cd×Vd 

where Co is the stock solution’s concentration, Vo is the volume of stock solution being diluted, Cd is the dilute solution’s concentration, and Vd is the volume of the dilute solution. Again, the type of glassware used to measure Vo and Vd depends on how precisely we need to know the solution’s concentration. 

MATERIALS REQUIRED: 

Conical Flask, Measuring Cylinder, Digital Balance (Sartorius), CuSO4, Distilled Water 

PROCEDURE: 

Weigh out accurately 0.20 g of copper(II) sulfate pentahydrate (CuSO4⋅5H2O) and dissolve it by adding to it about 100 mL of distilled water in a 250 mL beaker. Transfer the solution quantitatively to a 500 mL volumetric flask and make it up to volume and mix well. 

OBSERVATION: 

Transparent light blue coloured 100 ml of solution is prepared. 

INTERPRETATION: 

To prepare stock solution the weighing should be done properly otherwise the concentration can be changed than the required value. The digital weight balance should be used precisely to avoid an error in concentration. The solution should be mixed properly.