Table of Contents
Why do we see lower meniscus in Colourless solution?
In the case of colourless liquid, it is easy to observe the phase boundary, whether it is convex or concave hence in the colourless liquid lower meniscus may be considered. A meniscus is the curvature of the surface of the water. When students look at the surface, the water level is not straight.
Why do we see lower meniscus?
Most liquids have concave menisci because the molecules of those liquids are more strongly attracted to the walls of their container than to each other. The liquid ‘sticks’ to the walls instead of lying flat, causing the downward curve.
Which meniscus is seen in the burette containing KMnO4 solution and why?
Since the solution of KMnO4 is of dark colour, the upper meniscus should be considered for noting the burette readings.
How do you read a meniscus color?
If the meniscus is a concave meniscus, read at the lowest level of the curve. If the meniscus is convex, take your measurement at the highest point of the curve. The short answer: Take your measurement from the center of the meniscus. It’s that easy.
When measuring clear liquid such as water what meniscus level should it be read?
For water and most liquids, this is the bottom of the meniscus. For mercury, take the measurement from the top of the meniscus. In either case, you are measuring based on the center of the meniscus. For a flat meniscus, make sure the liquid is level.
How do you read a lower meniscus?
What is lower meniscus and upper meniscus in burette?
Concave menisci are read from the bottom of the curve at eye level. A meniscus is a curve formed on the upper surface of a liquid inside a container. This curve is formed by the surface tension between the liquid and the container holding the liquid. Convex menisci are read from the top of the curve at eye level.
Which meniscus is observed for KMnO4?
KMnO4 is a dark colour solution so always use upper meniscus reading. Use sulphuric acid for acidifying the potassium permanganate. Don’t use HCl or nitric acid. Maintain the temperature of oxalic acid solution at 50-60’C.