Question

Define molarity. The density of 3M solution of Nacl is 1.25g/L. Calculate the molality of solution

Answer 1

molarity is defines as the number of moles of solute divided by the number of liter of solution.
density =mass /volume
mass of 1 litter of Sol =1.25g/l*1000ml=1,250gms
v=volume of water added to make the sol
175.32gms+1gm/ml*v=1,250gm
v=1,074.68ml
so, 1,074.68ml or1,074.68gms of water is mixed with 3moles of back to make 3M sol
molarity =3/1.07468kg=2.7915molal