Answer:Water meniscus is concave, mercury meniscus is convex due to the differences in their cohesive and adhesive forces.
Explanation:This occurs with water and a glass tube. A convex meniscus occurs when the molecules have a stronger attraction to each other than to the container, as with mercury and glass.1. Cohesion refers to the attraction between molecules of the same substance, while adhesion refers to the attraction between molecules of different substances.
2. Water molecules have strong cohesive forces, which cause them to be attracted to each other and form a convex meniscus in a glass tube. This means that the center of the meniscus is higher than the edges, creating a curved shape.
3. On the other hand, mercury molecules have stronger cohesive forces compared to their adhesive forces with glass. This results in the mercury being more attracted to itself than to the glass, causing the meniscus to be concave. In this case, the center of the meniscus is lower than the edges, creating an inverted curved shape.
4. The differences in the cohesive and adhesive forces between water and mercury influence the shape of their menisci in a glass tube.
To further illustrate, imagine placing a droplet of water in a glass tube. The water molecules are attracted to each other, causing the droplet to form a convex meniscus. In contrast, if a droplet of mercury is placed in the same glass tube, the cohesive forces among the mercury molecules make it retract and create a concave meniscus.
In summary, the shape of the meniscus in a glass tube is different for water and mercury due to the varying strengths of cohesive and adhesive forces between these substances. Water forms a convex meniscus, while mercury forms a concave meniscus.