Laboratory Experiments of B.Sc. II Sem BT/FS/CBZ - Experiment: 3

 Laboratory Experiments of B.Sc. II Sem BT/FS/CBZ

 

Dr. Navdeep Sharma
Institute of Sciences
SAGE University, Indore (M.P.)

 

Experiment 3


Objective:

To calibrate a pH meter using standard buffer solutions of known pH values.

Apparatus and Materials Required:

  • Digital pH meter
  • Standard buffer solutions (pH 4.00, pH 7.00, and pH 9.20 or 10.00)
  • Distilled water
  • Beakers (3) – 50 mL each
  • Wash bottle
  • Tissue paper or filter paper
  • Glass rod
  • Measuring cylinder

Theory:

A pH meter measures the hydrogen ion concentration (acidity or basicity) of a solution. Calibration ensures accurate and reliable readings by setting the pH meter to known pH values before use. Buffer solutions with known pH values are used for calibration. Usually, a 2-point or 3-point calibration is performed.

Procedure:

  1. Preparation:
    • Switch on the pH meter and allow it to warm up for 5–10 minutes.
    • Rinse the electrode with distilled water and blot dry using tissue paper (do not rub).
  2. Calibration with pH 7 Buffer:
    • Pour a small amount of pH 7.00 buffer solution into a clean beaker.
    • Dip the electrode into the buffer solution and wait for the reading to stabilize.
    • Set the meter to read exactly pH 7.00 using the calibration knob.
  3. Calibration with pH 4 or pH 10 Buffer:
    • Rinse the electrode with distilled water and blot dry.
    • Pour pH 4.00 (for acidic range) or pH 10.00 (for basic range) buffer solution into a clean beaker.
    • Dip the electrode into the solution and allow it to stabilize.
    • Adjust the second calibration knob (slope) to read exact pH value of the buffer.
  4. Verification (Optional):
    • Repeat with a third buffer (e.g., pH 9.20) to check the accuracy.
  5. Final Rinsing:
    • Rinse the electrode again with distilled water.
    • The pH meter is now calibrated and ready for use.

Precautions:

  • Always use fresh standard buffer solutions.
  • Do not wipe or rub the electrode; gently blot dry.
  • Avoid contaminating the buffer solutions.
  • Keep the electrode immersed during use and store in suitable storage solution.

Result:

The pH meter was successfully calibrated using standard buffer solutions. It can now be used for accurate pH measurements.

 

Comments

Post a Comment

Popular posts from this blog

  Maceration: A Traditional yet Timeless Extraction Technique Dr. Navdeep Sharma Institute of Sciences SAGE University, Indore Maceration is one of the oldest and simplest methods of extracting bioactive compounds from plant material. Used widely in herbal medicine, pharmaceuticals and perfumery, maceration involves soaking plant material in a suitable solvent to extract desired compounds. This blog explores the detailed process of maceration, its underlying chemistry and its applications in modern industries. What is Maceration? Maceration is a liquid-solid extraction technique where plant material is immersed in a solvent at ambient or slightly elevated temperatures. Over time, the solvent dissolves the bioactive compounds from the plant matrix, resulting in a solution enriched with these compounds. The process is simple yet effective, making it suitable for small-scale and traditional extraction setups. Key Principles of Maceration Solubility: The success of macer...
Read more
  Key Factors Contributing to the Stability of Complex and Large Molecular Structures Achieving a stable molecular structure in complex molecules , large complex molecules and very large complex molecules is the result of several key factors that influence their stability at various scales. These factors range from basic electronic and bonding principles to more advanced structural considerations as molecular size increases. Below are the main contributors to stability across these different molecular scales: 1. Bonding and Electron Distribution (Fundamental for All Complex Molecules) Covalent Bonding : The formation of strong covalent bonds between atoms is the fundamental stabilizing factor. In smaller or moderately complex molecules, covalent bonding ensures that atoms achieve a stable electronic configuration (typically a full valence shell). Example: Water (H₂O) forms stable covalent bonds between oxygen and hydrogen, following the oct...
Read more
  Why Carbon-Carbon Quadruple Bonds Are Impossible: Orbital and Structural Limitations Explained A carbon-carbon quadruple bond does not exist due to several fundamental reasons rooted in the nature of carbon’s electron configuration, bonding limitations and spatial constraints. Let’s break down the key reasons why a quadruple bond between carbon atoms is not possible: 1. Electron Configuration and Orbital Availability Carbon has the electron configuration 1s² 2s² 2p² . To form a bond, carbon typically hybridizes its orbitals, such as sp³ , sp² , or sp hybridization, allowing it to form single , double , or triple bonds , respectively. To form a quadruple bond, four bonding interactions (two sigma and two pi bonds, for example) would be required. However, carbon atoms only have one available s-orbital and three p-orbitals (px, py, pz) for bonding. While it can form a single sigma bond (via sp or sp² hybridization) and two pi bonds ...
Read more