Which of the following terms are unitless?

(i) Molality

(ii) Molarity

(iii) Mole fraction

(iv) Mass percent

<p>This is a Multiple Choice Questions as classified in NCERT Exemplar</p><p>Option (C), (D)</p><p>Molality: It is defined as the number of moles of solute divided by the mass of solvent in kg . It is denoted by m . The formula is expressed as</p><p>m =<span contenteditable="false"> <math> <mfrac> <mrow> <mrow> <mi mathvariant="normal">n</mi> </mrow> </mrow> <mrow> <mrow> <mi mathvariant="normal">W</mi> <mi mathvariant="normal"> </mi> <mi mathvariant="normal"> </mi> </mrow> </mrow> </mfrac> </math> </span></p><p>The SI unit of molality is 1 mol/kg</p><p>Molarity: It is defined as the number of moles of solute divided by the volume of solution in latice. It is represented by M&nbsp; The formula of molarity is expressed as</p><p>M =<span contenteditable="false"> <math> <mfrac> <mrow> <mrow> <mi mathvariant="normal">n</mi> </mrow> </mrow> <mrow> <mrow> <mi mathvariant="normal">V</mi> <mi mathvariant="normal"> </mi> <mi mathvariant="normal"> </mi> </mrow> </mrow> </mfrac> </math> </span></p><p>Here, n is the number of moles of solute and V is the volume of solution expressed in liters. The SI unit of molarity is mol/ L .</p><p>Mole fraction (x ) : The mole fraction of a substance is defined as the number of moles of that substance divided by the total number of moles of all substances present in the solution.</p><p>Mass percent: it is defined as the weight of the solute divided by the total weight of the solution and the obtained result is multiplied by 100 in order to give a percent. Thus, mole fraction and mass percent are unitless.</p>

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