# Question : Concentration of 1 molar solution is     a) more than 1 molal solution     b) less than 1 molal solution

tarun garg
30 Points
10 years ago
concentration of 1 molar solution is higher than 1 molal solution.......since density of water=1 then 1 mole of solute is present is 1000 ml of water (1000ml=amount of (solute +solvent)) so mass of solvent would be less than 1000 g so 1 molar solution is more concentrated
Smriti Prakash Suman
4 Points
10 years ago

As per my understanding, whether one will be greater than the other will depend upon the density of the solvent.

Take for example- We take a solute like NaCl (which actually doesnt contribute to the volume of the solution after getting dissolved because it goes into the intermolecular spaces of the solvent) and water.

Water has a density of 1kg/L.

Therefore, if we are adding x moles of NaCl in 1L of  water, then,

Molarity= x Molar

Molality= x Molal (Since, 1L of water has a mass of 1kg)

Therefore, in this case, Molarity=Molality

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Now , consider the same x mloes of NaCl being mixed into 1L of any other solvent of density p kg/L such that p>1.

Then,

Molality= x Molar

Molality= x/p Molal (and you can see that x/p < x)

Therefore, in this case, Molality < Molarity.

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Finally, consider x moles of NaCl being mixed into 1L of any solvent of density q kg/L such that q<1.

Then,

Molarity= x Molar

Molality= x/q Molal ( and you can see that x/q > x)

Therefore, in this case, Molality > Molarity.