The molarity of an aqueous solution of glucose (C6H12O6) is $$0.01$$. To $$200$$ mL of the solution, which of the following should be carried out to make it $$0.02$$ M?I. Evaporate $$50$$ mL of solutionII. Add $$0.180$$ g of glucose and then evaporate $$50$$ mL of solutionIII. Add $$50$$ mL of waterThe correct option is:

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Since the molarity of glucose has to be increased (from$$ $$0.01$$ M to $$0.02$$ $$M), so this can be carried out either by evaporating the solution or by adding some more glucose.So, the only possible answer is (3)I$$.  Evaporate $$50$$ mL of solution mmoles of glucose initially $$=$$ $$0.01$$ x $$200$$ $$=$$ $$2$$ Volume after $$evaporation=$$ $$200$$ $$-$$ $$50$$ $$=$$ $$150$$ mL Mglucose $$=$$ mmoles $$VmL=2150=0.013MII$$. mmoles of glucose added $$=$$ $$0.180180$$×$$1000=1Total$$ mmoles of glucose $$=$$ $$2$$ $$+$$ $$1$$ $$=$$ $$3Volume$$ $$=$$ $$150$$ mL $$(after$$ evaporation of $$50$$ mL $$solution)Mglucose$$ $$=$$ $$3150=0.02MIII$$. Add $$50$$ mL of water:New volume of solution $$=$$ $$200$$ $$+$$ $$50$$ $$=$$ $$250$$ mLMglucose $$=2$$ $$mmol250$$ mL $$=0.008MHence$$ answer is $$(3)

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