Question

12.       What is responsible for capillary action, a property of liquids?

a)         surface tension

b)         cohesive forces

c)         adhesive forces

d)         viscosity

e)         two of these

32. Which of the following correctly states the relationship between temperature and the solubility of a substance in water?

a) The solubility of a substance in water increases as the temperature rises, especially for gases. b) The solubility of a substance in water decreases as the temperature rises, especially for ionic solids. c) The solubility of a substance in water with temperature cannot be accurately predicted, especially for ionic solids. d) The solubility of a substance in water decreases as the temperature lowers, especially for gases. e) Both A and D are correct.

Answer 1

Answer 12)

It's COHESIVE FORCE and ADHESIVE FORCE which are responsible for capilary action i.e. rise of liquid above the normal level in capilary.

Answer option (e) i.e. two of these i.e. (b) Cohesive and (c) Adhesive.

Cohesive force : These are the intermolecular forces (such as hydrogen bonding and Van der Waals forces) which cause a tendency in liquids to resist seperation.These forces exist between molecules of same substance.

Adhesive force : These are attractive forces between unlike molecules i.e. molecules of different substance.

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Answer 32)

a) The solubility of a substance in water increases as the temperature rises, especially for gases.

FALSE. Actually with increasing temperature solubility of gases decreases.

b) The solubility of a substance in water decreases as the temperature rises, especially for ionic solids.

FALSE Actually with increase in temperature solubility of ionic solids increases in water.

c) The solubility of a substance in water with temperature cannot be accurately predicted, especially for ionic solids.

TRUE :

d) The solubility of a substance in water decreases as the temperature lowers, especially for gases.

FALSE

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