Lec-36_Measurement of conductance_part 2 I Applied Chemistry I Chemical Engineering

This paragraph introduces Sugruti Joshi from NP Institute of Engineering and Technology, who is going to conduct a video lecture series on Applied Chemistry with the subject code 3130506. The focus is on the experiments of applied chemistry, which include both qualitative and quantitative analysis. The experiments are designed to use analytical techniques and instruments to determine the quality and quantity of a substance, whether it's a mixture or a pure substance. The session continues with an explanation of experiment number one, which involves the measurement of conductance using two different solutions, HCl and NaOH. The importance of using a conductivity meter for finding the exact neutralization point is emphasized, and the required apparatus for the experiment is listed, including a conductometer, conductivity cell, beaker, pipette, burets, conical flask, and measuring cylinder. The paragraph concludes with a description of the conductivity cell and the digital conductivity emitter, highlighting their use in the experiment.

This paragraph delves into the concept of conductance, which is the ability of a substance or solution to pass electric current, facilitated by ions. The specific conductance of a solution is measured in this session. The principle of conductivity, or conductometry, is explained, particularly how the conductance of a solution changes when hydrochloric acid (HCl) is titrated with sodium hydroxide (NaOH). The paragraph describes how the highly mobile hydrogen ions in HCl are replaced by slower moving sodium ions from NaOH, leading to a decrease in conductance. The process continues until all H+ ions have combined with OH- ions to form water, and the conductance rises sharply due to the presence of excess, highly mobile hydroxide ions. The paragraph concludes with a discussion on how the neutralization of a strong acid by a strong base leads to minimum conductance at the end point, and the subsequent increase in conductance due to the presence of highly mobile OH- ions. A graph illustrating the relationship between conductance and the volume of base added is also mentioned.

The final paragraph outlines the procedure for measuring the conductivity of a solution to determine the strength of an unknown acid solution. It begins by stating the given solution and the provision of a normal NaOH solution. The conductivity cell is rinsed with conductivity water or double distilled water to remove impurities. The procedure involves pipetting 20 ml of the HCl solution into a beaker and immersing the conductivity cell in it. The temperature of the sample solution is noted and set in the instrument. NaOH is added in small amounts, measuring the conductance after each addition until the conductance reaches its lowest point, indicating the neutralization point. Readings are taken and recorded in an observation table. The paragraph concludes with the calculation process, using the formula v1 * s1 = v2 * s2, where v1 is the volume of HCl, s1 is the strength of HCl, v2 is the volume of NaOH at the neutralization point, and s2 is the strength of NaOH. The strength of the given HCl solution is determined and concluded based on the calculations. The paragraph ends with a note on continuing the discussion in the next session.