We can dilute an aqueous solution by adding liquid water to the solution, resulting in a less concentrated solution. Which of the following would result in a more concentrated solution?

(A) decreasing the number of moles of solute
(B) adding ice to the solution and allowing the ice to melt
(C) evaporating some of the water contained in the solution
(D) none of the above

= C

Explanation:

evaporating some of the water contained in the solution will increase the concentration of the resulting solution, because there will be concomitant increase in the number of moles of the solute left in the solution.

answer: enthalpy

explanation:

for a exothermic reaction, the energy is released i.e. the energy of the products is lower than the energy of the reactants.

= enthaply

= energy of products

= energy of reactants

as , thus comes out to be negative. negative value of enthalpy shows that the reaction is exothermic.