Question

If an aqueous solution is very dilute, will its molality be greater than its molarity, nearly the same as its molarity, or smaller than its molarity?

Answer 1

Molality stays nearly the same as its molarity

Step-by-step explanation:

Let's make an example of this:

An aqueous solution of 1 mol of NaCl is diluited in a volume of 1L (A).

The same solution is diluited in a volume of 1L, but now we have 0.00001 moles of NaCl (B)

Solution A → Concentrated, [NaCl] = 1 M, 1 m

1L = 1kg

Solution B → Diluted, less concentration, Less molarity and molality.

Now, solution B has a volume of 5L, with 2 moles of solute while A, stays the same.

Molarity A = 1M

Molality A = 1m

Molarity B = 0.4 M

Molality B = 0.4 m

In conclussion, stays nearly the same as its molarity