Maximizing Safety and Accuracy in Titration: Tips for Volumetric Analysis

In summary, the conversation is about a student's struggles with mouth pipetting during a chemistry practical. They mention the rule of using their mouth and the difficulty in getting the exact 20ml of solution. Someone suggests using a finger to close the pipette and letting excess solution drop out to reach the mark. Another person criticizes the practice of mouth pipetting and suggests using a pipette filler. The conversation also touches on the issue of safety and the cost of safety equipment in different parts of the world.
  • #1
smart_worker
131
1
guys today i have my chemistry practicals.i have to do titration.i have to suck the pipette with my mouth.it is a rule that everyone must use their mouth only.it is very difficult for me to suck in exact 20ml of the solution and pipette out.so i am not getting the exact titre value.are there any shortcuts to find the titre value.
 
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  • #2
You don't "suck exactly 20 mL". You suck more, use your finger to close the pipette, then you let the excess to drop out till the pipette is filled exactly to the mark.
 
  • #3
Utterly ridiculous that in 2014 people are still being taught to mouth pipette. I thought this practice was prohibited almost everywhere.
 
  • #4
gravenewworld said:
Utterly ridiculous that in 2014 people are still being taught to mouth pipette. I thought this practice was prohibited almost everywhere.

Sorry to say that, but you are just showing your ignorance - not every part of the world is rich enough.
 
  • #5
smart_worker said:
are there any shortcuts to find the titre value.

You can't decide the concentration of a solution while looking at it. And you are not allowed to do more than that. One shortcut is to get to know the titre value first!
In my case the error was always due to leftover distilled water in the flask. It diluted the pipetted solution and I purposely used to take 0.1mL less than the observed titre value. It worked well for me!
 
  • #6
Borek said:
Sorry to say that, but you are just showing your ignorance - not every part of the world is rich enough.

Yup, so expensive :rolleyes:

http://www.sciencelabsupplies.com/Pipette_Filler_Red.html


If you can afford to do chemistry, afford chemicasl, afford to have a lab, and afford glassware you can afford minor safety items that can prevent major injuries. Hey mouth pipetting, what a great way to get hepatitis or oral acid/base burns!
 
  • #7
You are still not understanding the reality - this kind of safety is considered a luxury in many places. When GDP per capita is 50 times lower than in US, $5 is a serious expense.

And - without getting into details - OP doesn't live in US.
 

1. What is volumetric analysis?

Volumetric analysis, also known as titration, is a quantitative analytical technique used to determine the concentration of a substance in a solution by measuring the volume of a known reactant required to completely react with the analyte.

2. What are the common types of volumetric analysis?

The common types of volumetric analysis include acid-base titrations, redox titrations, precipitation titrations, and complexometric titrations.

3. How do you choose the appropriate indicator for titration?

The choice of indicator for titration depends on the type of titration being performed and the pH range at which the indicator changes color. It is important to choose an indicator that changes color within the pH range of the equivalence point of the titration.

4. What are the sources of error in volumetric analysis?

The sources of error in volumetric analysis include inaccurate measurements of volume, improper calibration of equipment, incorrect preparation of solutions, and human error in reading burette volumes or adding reagents.

5. How can you improve the accuracy of volumetric analysis?

To improve the accuracy of volumetric analysis, it is important to properly calibrate equipment, use high-quality reagents, accurately measure volumes, and perform multiple trials to ensure consistency in results. It is also important to carefully choose the appropriate indicator and perform the titration slowly and carefully.

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