Question

0.1 gram mole of urea is dissolved in 100g of water. The MOLALITY of the solution is?

Answer 1

AnSwEr:—

$\longrightarrow$The molality of the solution is 1 m

$\rule{200}2$

SteP By SteP ExplainaTion:—

★Molality is defined as the number of moles of substance present in a 1 kg of a solution. It is denoted by 'm'.

Formula:

m = no. of moles/given mass in kg

here

• No. of moles of urea dissolved = 0.1 gram moles

• Given mass in kg = 100g = 100/1000= 0.1 kg

putting these values in the above formula we get;

$\longrightarrow \:{ \tt{ \frac{ \cancel{0.1}}{ \cancel{0.1} }}} \\ \\ \longrightarrow \: { \boxed{ \bf{1 \: m}}}$

Answer 2

Answer:

1 molal

Explanation:

Molality :

It is defined as numbers of moles of solute present in unit amount of solvent in kg.

m = No. of moles of solute / mass of solvent in kg.

We have given :

No. of moles = 0.1 moles

Mass of solvent = 100 g

Now :

m = ( 0.1 × 1000 ) / ( 100 )

m =  ( 0.1 × 10 )

m = 1 molal

Hence we get required answer.