When water and mercury falls on glass surface water wets the surface but mercury doesn t?

When water and mercury falls on glass surface water wets the surface but mercury doesn t?

Cohesive forces between water molecules is much lesser than adhesive forces between water and glass molecules and that’s why water tends to spread out on glass whereas cohesive forces within mercury is comparable to adhesive forces between mercury and glass and that’s why mercury tends to form drops.

What are cohesive and adhesive forces explain why water wets the glass surface but mercury does not?

The forces of adhesion between the molecules of water and glass is more than the forces of cohesion between the molecules. Due to this, water wets the glass surface.

Why does mercury not cling to glass?

The force of cohesion between mercury molecules is much greater than force of adhesion between mercury and glass. Therefore, mercury does not cling to glass.

Why does mercury not wet wood?

The higher the adhesive forces, the more likely a liquid is supposed to make the surface of contact wet. As it is told in the question that mercury does not wet glass, wood or iron, it is so because the cohesive forces are greater than the adhesive forces for the respective substances.

How can you reduce the surface tension of a liquid?

Some liquids such as oil and kerosene can destroy surface tension in water. Adding soap or detergent reduces surface tension in water. Increasing the temperature of the liquid reduces surface tension.

What is the difference between mercury and water?

Mercury has a density of 13.5 g/mL, which is about 13.5 times denser than water (1.0 g/mL), so a small amount of mercury like this feels unexpectedly heavy. Because liquid mercury expands and contracts in a predictable fashion with temperature, it can be used in thermometers, such as the lab thermometer shown below.

What is water surface tension?

The surface tension of water is about 72 mN/m at room temperature which is one of the highest surface tension for liquid. There is only one liquid having higher surface tension and that’s mercury which is a liquid metal with a surface tension of almost 500 mN/m.

Why does water spread on glass?

Forces of attraction between a liquid and a solid surface are called adhesive forces. Water wets glass and spreads out on it because the adhesive forces between the liquid and the glass are stronger than the cohesive forces within the water.

In which state of matter the force of cohesion is maximum?

Force of cohesion is maximum in solid state and minimum in gaseous state.

What increases the surface tension of water?

The Presence of ImpuritiesThe presence of impurities on the surface of, or dissolved in, a substance directly affects the surface tension of the liquid. The surface tension of water, for example, will increase when highly soluble impurities are added to it.

Which liquid has highest surface tension?

Besides mercury, water has the highest surface tension for all liquids, which is due to the hydrogen bonding in water molecules.

How can you increase the surface tension of water?

Compounds that lower water’s surface tension are called surfactants, which work by separating the water molecules from one another. Adding salt to water does increase the surface tension of water, although not by any significant amount. …

Why is Mercury considered a non wetting liquid?

Mercury is a non wetting liquid as it does not wet the surface in which it is kept as the cohesion forces within the drops are stronger than the adhesive forces between the drops and the surface. Because of its high surface tension it doesn’t wet most surfaces .it is analogous to water droplet formation on lotus leave.

Why does water wet a glass of water?

Water wets glass because (force of) adhesion/attraction between glass and water molecules is greater than (force of) cohesion/attraction of water molecules.

Why does liquid mercury have a convex shape?

Mercury does not wet glass – the cohesive forces within the drops are stronger than the adhesive forces between the drops and glass. When liquid mercury is confined in a tube, its surface (meniscus) has a convex shape because the cohesive forces in liquid mercury tend to draw it into a drop.

Is it true that Mercury does not wet skin?

Mercury does not wet skin or a number of other surfaces. It does wet copper, gold, silver and a few other metals.