Orsat apparatus

I think I speak for everyone that has ever used an Orsat when I say...Buy an electric unit like TESTO and you wont have the frustration.

Orsat Apparatus

The Orsat apparatus is used to measure volumes of carbon dioxide, oxygen and carbon monoxide within a fixed volume of a sample gas (100cc). However it is not particularly accurate at detecting very low concentrations.

The Orsat apparatus works using a very simple method. To find the volume of a particular gas within the sample a fixed volume of the sampled gas is passed through a specific solution which absorbs only the required gas. The remaining volume of the gas can then be re- measured and compared with the original volume to find the proportion of a specific gas within the sample.

The sampled gas is passed through a sequence of solutions each removing one of the gases and the remaining volume calculated afterwards. A solution of caustic potash is used to absorb the carbon dioxide, a mixture of pyrogallic acid, caustic potash and water is used to absorb the oxygen, and to remove the carbon monoxide a solution of cuprous chloride is used.

BUT AS SUGGESTED USE ELECTRONIC TESTING, IT IS MORE ACCURATE.

Yes use electronic testing as suggested by others how ever if you are interested refer Vogel's Analytical Chemistry for basics of analytical chemistry

crm

why we use caustic potash and water?

what precaution should be a taken to ensure good results in the test?

This apparatus was used as one of the lab experiments for the students doing their Diploma in Mechanical Engineering. I taught this some thirty years ago.........the memory may be a bit rusty........but , to get an accurate a result as possible, make sure that your solutions are mixed correctly and the stoppers and rubber tubing are in good condition and air tight. Also do not try to hurry the result.....take your time.

However, as pointed out before the Orsat Apparatus is not known for its accuracy.

which solution is absorb the methane gas?

I used an "orsat" for checking the quality of recovered gas after the autoclave reaction for the manufacture of PVC.

Bromine Water, and a pyroallol solution were two of the obnoxious liquids used.

The secret in using the apparatus is to always watch the rising liquid, and make sure that the line from the sampling point and the measuring cylinder are purged with the sampled gas

The apparatus was still in use at the ICI PVC plants when I retired in 1985.

Also make sure that the carrying handle at the top of the apparatus us secure, it makes a hell of a mess of the apparatus if it breaks loose coming down a steel staircase from the top of a chemical plant.