Question

Why is NaCl added to icy roads? a) It causes the Na+ ions to cluster together. b) The NaCl keeps the ice from melting c) The coating provides traction for tires. D) It lowers the freezing point of water.

36. Molecules whose water solutions conduct electric current ______________. a) are nonpolar b) ionize in water c) do not dissolve in water d) decompose in water

37. Which of the following does NOT increase the rate at which a solid dissolved in water? a) raising the temperature b) stirring c) using large pieces of the solid d) crushing the solid

38. Raising the temperature of a solvent causes solvent-solvent collisions to become _________. a) less frequent and more energetic b) more frequent and more energetic c) less frequent and less energetic d) more frequent and less energetic

39. Solubility of a solute depends on ____________. a) the nature of the solute and the temperature b) the nature of the solute only c) the temperature only d) neither the nature of the solute nor the temperature

40. A solution that contains a high concentration of solute but that can hold even more solute is ______. a) unsaturated and dilute b) saturated and dilute c) unsaturated and concentrated d) saturated and concentrate

Answer 1

35. When Ionic salt like NaCl is added to icy roads, it helps in lowering the freezing point of water and makes it more difficult to freeze. Salt acts as ice melter. So, the answer will be option D

36. Ions are responsible for conducting electricity in water. So, molecules whose water solutions conduct electric current ionizes in water. Answer will be option b.

37. Rate of chemical reaction at which solid dissolved in water can be increased by increasing the temperature, stirring the solution(agitation increases vibration and thus rate), increasing the surface area (i.e,Crushing the solid increases its surface area). But using larger pieces of solid decreases the rate of reaction. So, the answer will be option c.

38. Increasing the Temperature increases the kinetic energy of solvent molecules. Thus the collision will be more frequent and more energetic.

39. Solubility of as solute depends on:

• nature of solute and solvents: If both are polar or both are non-polar, they will dissolve easily as like dissolves like
• Temperature: Increases the solubility

So, the answer will be option a.

40. A solution containing high concentration of solute is called concentrated. And if a concentrated solution have capacity to hold more solute, it means the solution is unsaturated. So, the answer will be option c.

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