I'am unable to identify which is upper meniscus and lower meniscus while taking a solution in burette.please tell me how to identify it easily.
I can't tell you how to do it. Here is a web site that shows a picture. The best picture is second from left and has a black section below two on the buret. It shows a meniscus about 1.4 mL but you can clearly see the upper part and the lower part.
In practice some students have trouble seeing the lower meniscus; I show them two tricks of the trade.
1. place a black card behind the buret and that makes the lower meniscus show up better.
2. Placing the finger of one hand behind (but not EXACTLY behind). The easiest way is to place the finder BELOW the meniscus, then slowly raise the finger to higher levels. At a point BELOW the meniscus the lower point of the meniscus reflects from the finger and makes it very visible.
https://www.google.com/search?q=picture+meniscus+in+burette&hl=en&client=firefox-a&hs=dmZ&rls=org.mozilla:en-US:official&prmd=imvns&tbm=isch&tbo=u&source=univ&sa=X&ei=Y-NhUPPlF4nu2gXL2ICwBg&ved=0CCQQsAQ&biw=677&bih=385
To identify the upper and lower meniscus while taking a solution in a burette, you can follow these steps:
1. Fill the burette with the solution you want to measure, ensuring that the liquid level is above the tap or stopcock at the bottom.
2. Adjust the tap or stopcock to allow a steady flow of solution to come out of the burette.
3. Make sure the burette is placed on a level surface with the meniscus at eye level, which will make it easier to observe.
4. Look at the liquid surface inside the burette and locate the curved line where the liquid meets the glass. This curve is known as the meniscus.
5. The upper meniscus is the top part of the curve where the liquid appears to be higher due to surface tension. It usually appears as a concave downward curve.
6. The lower meniscus is the bottom part of the curve where the liquid appears to be lower due to surface tension. It usually appears as a convex upward curve.
Remember, when taking measurements, it is important to read the volume at the bottom of the meniscus to ensure accuracy. The volume can be read from the scale near the burette.
By following these steps, you can easily identify the upper and lower meniscus while using a burette.