There are two numericals, 1. Density of Methanol is 0.793 kg/l. Find molarity. ANSWER is : Desity/ Molar mass = Molarity (UNDERSTANDABLE) In other numerical 2. Concentration of H2SO4 is 98% by mass having density of 1.84gm/ml. Calculate Molarity. here they used another formula. now my question is, How second question is different from First ? why didnt they took density and devided it by Molar mass to get molarity? What I am missing?