Question

Density of 5 molar aqueous
solution of urea is
1.3 g/ml at 298 K. the molality of solution is
(a) 5m
(c) 5.25m
(6) 4.5m
(d) 4.2m​

Answer 1

Answer:

molatity of solution 5.25 m

Answer 2

Answer:

The solution's molality measured is $5$ molal.

Therefore, option a) $5m$ is the correct choice.

Explanation:

Given,

The molarity of the aqueous solution of urea, M = $5 molar$

The aqueous solution of urea's density, ρ = $1.3g/ml$

The molality of the solution, m =?

As we know,

• The molar mass of urea, $M^{'}$ = $60.06 g/mol$

Now,

• The molality of the solution in terms of given density and the molarity of solution can be calculated by the equation given below:
• $\frac{1}{m} = \frac{d}{M} - \frac{M^{'} }{1000}$

After putting the given values in the equation, we get:

• $\frac{1}{m} = \frac{1.3}{5} - \frac{60.06 }{1000}$
• $\frac{1}{m} = 0.26- 0.06$
• $\frac{1}{m} = 0.2$
• m = $5$ molal

Hence, the solution's molarity = $5$ molal.