Question

SUMMARY OF LEARNING OBJECTIVES Jo nos bas Adding solute (solid) to an unsaturate orute (solid) to an unsaturated solution causes the concentration of the solution to: INCREASE /DECREASE/ REMAIN UNCHANGED. aing pure water to a saturated solution will cause the concentration of the solution to: INCREASE /DECREASE/ REMAIN UNCHANGED. 1109 Adding a solid salt to a saturated solution cases the concentration of the solution to: INCREASE/DECREASE/ REMAIN UNCHANGED. Evaporation acting on an unsaturated solution causes the concentration of the solution to: INCREASE /DECREASE/ REMAIN UNCHANGED Evaporation acting on a saturated solution causes the concentration of the solution to: INCREASE /DECREASE/ REMAIN UNCHANGED.

Answer 1

Concentration of a solution is the amount of solute present in given volume of solution.

Concentration=Amount of solute/Volume of solution

So concentration is directly proportional to amount of solute and inversely proportional to volume of solution

Unsaturated solution means more amount of solute can be added to the solution. Saturated solution is the solution in which no more amount of solute can be dissolved.

If we add solute to an unsaturated solution, this increases the amount of solute in the solution i.e. it increases the concentration of solution.

If we add pure water to a saturated solution, this increases the amount of solvent and thus increases its volume, therefore the concentration of solution decreases.

If we add a solid salt to a saturated solution, no more salt will dissolve in the solution as it is a saturated solution. Therefore the concentration of solution remains unchanged.

Evaporation (a surface phenomenon in which surface particles of a liquid get converted to vapor phase below its boiling point) acting on an unsaturated solution decreases the volume of solution as some of the solvent gets converted to vapour phase, this causes the concentration of solution to increase as the amount of dissolved solute remains same despite a decrease in volume of solution.

If evaporation acts on a saturated solution, as the solvent evaporates it will cause the solid solute to form (as the solution is saturated and solvent remaining after evaporation can accomodate lesser amount of solute in dissolved form). Thus the concentration of the solution remains unchanged as it remains saturated.