1. Stalagmometer is cleaned to remove grease with the help of ____________
a) Chromic acid
b) Sulphuric acid
c) Distilled water
d) Tartaric acid
Explanation: Stalagmometer is cleaned to remove grease with the help of chromic acid. It is used for the determination of surface tension.
2. The surface tension of water at 250C is ____________
a) 90.0 dynes/cm
b) 45.63 dynes/cm
c) 82.5 dynes/cm
d) 72.14 dynes/cm
Explanation: The surface tension of water at 250C is 72.14 dynes/cm. It is a standard value.
3. On increasing the temperature, the kinetic energy of the liquid molecules ____________
a) Increases
b) Decreases
c) Remains constant
d) None of the mentioned
Explanation: On increasing the temperature, the kinetic energy of the liquid molecules also increases. At high temperatures, randomness increases.
4. In case of water and glass, we get a concave meniscus because the adhesive force between water and glass are _______________ than the cohesive forces between water molecules.
a) Weaker
b) Stronger
c) Same
d) None of the mentioned
Explanation: In the case of water and glass, we get a concave meniscus because the adhesive force between water and glass are stronger than the cohesive forces between water molecules.
5. Shapes of drops of liquid are spherical because of ____________
a) Viscosity
b) Conductivity
c) Absorption
d) Surface tension
Explanation: Shapes of drops of liquid are spherical because of surface tension as it reduces the surface area to a minimum.
6. Select the incorrect statement from the following option.
a) In case of mercury and glass, we observe a convex meniscus
b) Surface tension is responsible for the rise and fall of the capillary tubes
c) If two drops encounter each other, they tend to repel each other
d) All of the mentioned
Explanation: If two drops encounter each other, they tend to coalesce into a large drop. All the other options are correct. In the case of mercury and glass, we observe a convex meniscus and Surface tension is responsible for the rise and fall of the capillary tubes.
7. On increasing the temperature, the surface tension of the liquid ____________
a) Increases
b) Decreases
c) Remains constant
d) None of the mentioned
Explanation: On increasing the temperature, the surface tension of the liquid decreases. It is inversely proportional to the temperature.
8. Which of the following is an application of surface tension?
a) Use of soaps and detergents as cleansing agents
b) Molecular structure can be elucidated by surface tension measurements through parachor values
c) Surfactants are incorporated in preparations like toothpaste
d) All of the mentioned
Explanation: Use of soaps and detergents as cleansing agents, molecular structure can be elucidated by surface tension measurements through parachor values and surfactants are incorporated in preparations like toothpaste are the applications of surface tension.
9. Fractional distillation is a process of separation of ____________
a) 2 miscible liquids
b) 2 immiscible liquids
c) 1 miscible and 1 immiscible liquid
d) None of the mentioned
Explanation: Fractional distillation is a process of separation of 2 immiscible liquids. Fractional distillation is the separation of a mixture into its component parts, or fractions, separating chemical compounds by their boiling point by heating them to a temperature at which one or more fractions of the compound will vaporize.
10. The difference in boiling point of 2 liquid in fractional distillation is ____________
a) Greater than 25 K
b) Less than 25 K
c) Equal to 25 K
d) None of the mentioned
Explanation: Difference in the boiling point of 2 liquid in fractional distillation is is less than 25 K. Fractional distillation is the separation of a mixture into its component parts, or fractions, separating chemical compounds by their boiling point by heating them to a temperature at which one or more fractions of the compound will vaporize.