## What are the characteristics of an angle?

An angle is typically classified into four categories including acute, right, obtuse, and straight. An acute angle is one which has a degree measurement greater than 0° but less than 90°. A right angle has a 90° angle measurement.

## What is the physical significance of angle of contact?

Significance of Angle of Contact

Angle of contact determines whether a liquid will spread on the surface of a solid or it will form droplets on it. If the Angle of contact is obtuse:then droplet will be formed. If the Angle of contact is acute: then the water will spread.

## What is called angle of contact?

The angle which the tangent make to the free surface of the liquid at the point of contact with the walls of the vessel inside the liquid is called the angle of contact, or it is defined as the angle subtended between the tangents drawn at the liquid surface and the solid surface inside the liquid at the point of

## Which factors affect angle of contact?

Two factors affecting the angle of contact:
• The nature of the liquid and the solid in contact.
• Impurities present in the liquid change the angle of contact.

## Which factors does not affect angle of contact?

Which of the following factor will not affect the value of angle of contact? The angle of contact does not depend on the pressure of the liquid.

## Does angle of contact depend on temperature?

It means, if the temperature increases, angle of contact decreases due to decrease cohesive force and if the temperature decreases, angle of contact increases due to increase cohesive force.

## What is the effect of impurities on angle of contact?

Surface tension generally decreases on increasing the temperature i.e adhesion increases. Hence, angle of contact will increase. In case of impurities, when a highly soluble impurity like NaCl is added to water, surface tension increases whereas it decreases for sparingly solube (eg: phenol) or insoluble impurities.

## What is effect of temperature of liquid on angle of contact?

With the increase in temperature , the surface tension of liquid decreases. Due to it, the liquid surface on the solid surface becomes more flat, consequently the angle of contact of a liquid increases with the increase in temperature.

## What is the effect of impurity on angle of contact?

For the explanation of why it increases with increase in temperature, I found out that the surface tension causes the increase in cohesive forces and hence a upward concave.

## When a detergent is added in water the angle of contact?

When the detergent is added with water then the angle of contact is decreased . Because small angle of contact will help in capillary rise of the water which will ultimately help in the detergent mixed water to mix up with the clothes at a faster rate . Aakash EduTech Pvt.

## Why do detergents have small angle of contact?

Water with detergent dissolved in it has small angles of contact (θ). This is because for a small θ, there is a fast capillary rise of the detergent in the cloth. The capillary rise of a liquid is directly proportional to the cosine of the angle of contact (θ).

## What will be the effect of increasing temperature on angle of contact and surface tension?

Angle of contact increases with increase of temperature while surface tension generally decreases with increase of temperature.

## When temperature is increased the angle of contact is?

As the temperature increases, the surface tension and cohesive force among liquid molecules weakens, so the angle of contact with solid surface decreases.

## For which of the two pairs the angle of contact is same?

Both liquids water and alcohol have same nature (ie, wet the solid). Hence, angle of contact for both is acute.

## What will be the effect of increasing temperature on surface tension?

As temperature increases, molecules of liquid become more active and they move more rapidly; therefore, the intermolecular forces are more instable. Surface tension decreases with increasing temperature.

## What factors affect surface tension?

As temperature decreases, surface tension increases. Conversely, as surface tension decreases strong; as molecules become more active with an increase in temperature becoming zero at its boiling point and vanishing at critical temperature. Adding chemicals to a liquid will change its surface tension characteristics.

## How do impurities affect surface tension?

As the concentration of the impurity increases the equilibrium surface tension decreases. The decrease in the equilibrium surface tension is also dependent upon the concentration of the tetradecylpyridinium bromide. As the concentration of the surfactant (TPB) increases the effect of the impurity is reduced.

## What happens when surface tension decreases?

Washing with cold water: The major reason for using hot water for washing is that its surface tension is lower and it is a better wetting agent. But if the detergent lowers the surface tension, the heating may be unnecessary. Surface tension and droplets: Surface tension is responsible for the shape of liquid droplets.

## Does salt increase surface tension?

The surface tension does increase when the salt is added to the water so that means that the penny drop experiment is mostly affected by the water’s cohesive forces.

## Does pH affect surface tension?

At pH < 0 the surface tension decreases significantly, indicating adsorption of HCl from strong acid solutions. At pH > 13 the surface tension increases, indicating a lower surface concentration of hydroxide ion than in the bulk solution. The surface tension is given by the Gibbs Eq.