Question

150 ml of ethyl alcohol liquid in 1 litre of water calculate molalityof ethyl alcohol . (density =.764 of ethyl alcohol)​

Answer 1

Answer:

density of ethyl alcohol = 764 kg/ dm^3

so that 150 ml= 0.15 dm^3 CH3OH = 0.15 * 764 g = 114.6 g

it's molar mass= 46g/ mol

no. of moles of CH3OH = 114.6/46= 2.5 moles

density of water= 1000kg/ lit

so that mass of 1 lit water= 1000kg

molality = no. of moles of solute/ mass of solvent in kg

=2.5/1000

=2.5 * 10^-3