The meniscus of mercury in a glass tube is convex because: there is a lower attraction of mercury to the glass than to itself.
Surface tension can be defined as a property of liquid such as mercury, which makes its surface to resist an external force due to the cohesive nature of the liquid's molecules.
This ultimately implies that, the surface tension of a mercury is highly dependent on the cohesive forces of attraction existing between its molecules.
In conclusion, a convex meniscus of mercury in a glass tube is due to the effect of high surface tension because it causes the mercury to be more attracted to itself than to the glass, while minimizing (limiting) the total surface area rather than maximizing it.
Read more on surface tension here: https://brainly.com/question/7597385
