Question

In which of the following pieces of glassware does a meniscus become of importance?
A. Watch glass
B. Burette
C. Beaker
D. Flask
E. Funnel

Answer 1

Hint:The meniscus is the curve in the upper surface of a liquid close to the surface of the container or another object, caused by surface tension. It can be either concave or convex, depending on the liquid and the surface. Adhesive liquids form concave meniscus and cohesive liquids form a convex meniscus.

Complete answer:

A concave meniscus in case of water.

A convex meniscus in case of mercury. Flasks and beakers have very large mouths so we can't observe any kind of meniscus in them so meniscus doesn't have any kind of importance here.A watch glass is a circular concave piece of glass used in chemistry as a surface to evaporate a liquid, to hold solids while being weighed for heating a small amount of substance and as a cover for a beaker.

Since these deal with solid meniscus doesn't play any role.A burette has a very small mouth less than an inch. We can see the meniscus in it clearly and in this case, the meniscus plays an important role in reading the volume of the liquid that is present in it.It is done by lining the lowermost point of the meniscus with the markings present.

Note:Meniscus only occurs if the diameter is quite small, like nearly 1 inch approximately, if it gets bigger then meniscus is not visible. In the case of mercury, the meniscus formed is of a convex type. So, if we ever need to take the volume measurement of mercury in a burette we will in-line the uppermost point of the convex meniscus with the markings present in the burette for correct measurements.