Answer
396.9k+ views
Hint: A solution is made up of solvent and solute. non-volatile solute means which does not evaporate . It has high boiling points and less vapour pressure . we can also say that substances which have boiling point ${100^ \circ }C$ or more are termed as volatile rest all are non-volatile .
Complete answer:
Vapour pressure of water at normal boiling point given is $1.013bar$
Vapour pressure given for solution in normal boiling point is $1.004bar$
Given that solute \[4\% \] means $4g$
Mass of solvent will be $100 - 4 = 96g$
Molar mass of water is $18gmo{l^{ - 1}}$
Now we have to apply Raoult’s law
$ \Rightarrow $ $\dfrac{{{p_1}^0 - {p_1}}}{{{p_1}^0}} = \dfrac{{{w_2} \times {M_1}}}{{{M_2} \times {w_1}}}$
Which states that vapour pressure of a solution of non-volatile solute should be equal to the vapour pressure of the pure solvent at that temperature which is multiplied with mole fraction.
Putting all the values
$ \Rightarrow $ $\dfrac{{1.013 - 1.004}}{{1.013}} = \dfrac{{2 \times 18}}{{{M_2} \times 96}}$
${M_2} = 84.42gmo{l^{ - 1}}$
Hence the molar mass of the solute is $84.42gmo{l^{ - 1}}$
So the correct answer is Option B.
Additional information:
There are four types of colligative properties which are: vapour pressure, elevation in boiling point, depression in freezing point and osmotic pressure. Colligative is a Latin word which means bounds together.
Colligative properties are those which depend upon the number of solute particles not on the nature of the solution. Basically it does not affect the types of solute present in the solvent only the number of solutes are actually present that matters.
Note:
Remember Raoul’s law only works for lower concentration . Also the interactions of solute and solvent must be identical. As the intermolecular forces vary a lot between the molecules so only by keeping the concentration of solute low we can minimise the intermolecular forces.
Complete answer:
Vapour pressure of water at normal boiling point given is $1.013bar$
Vapour pressure given for solution in normal boiling point is $1.004bar$
Given that solute \[4\% \] means $4g$
Mass of solvent will be $100 - 4 = 96g$
Molar mass of water is $18gmo{l^{ - 1}}$
Now we have to apply Raoult’s law
$ \Rightarrow $ $\dfrac{{{p_1}^0 - {p_1}}}{{{p_1}^0}} = \dfrac{{{w_2} \times {M_1}}}{{{M_2} \times {w_1}}}$
Which states that vapour pressure of a solution of non-volatile solute should be equal to the vapour pressure of the pure solvent at that temperature which is multiplied with mole fraction.
Putting all the values
$ \Rightarrow $ $\dfrac{{1.013 - 1.004}}{{1.013}} = \dfrac{{2 \times 18}}{{{M_2} \times 96}}$
${M_2} = 84.42gmo{l^{ - 1}}$
Hence the molar mass of the solute is $84.42gmo{l^{ - 1}}$
So the correct answer is Option B.
Additional information:
There are four types of colligative properties which are: vapour pressure, elevation in boiling point, depression in freezing point and osmotic pressure. Colligative is a Latin word which means bounds together.
Colligative properties are those which depend upon the number of solute particles not on the nature of the solution. Basically it does not affect the types of solute present in the solvent only the number of solutes are actually present that matters.
Note:
Remember Raoul’s law only works for lower concentration . Also the interactions of solute and solvent must be identical. As the intermolecular forces vary a lot between the molecules so only by keeping the concentration of solute low we can minimise the intermolecular forces.
Recently Updated Pages
How many sigma and pi bonds are present in HCequiv class 11 chemistry CBSE
![arrow-right](/cdn/images/seo-templates/arrow-right.png)
Why Are Noble Gases NonReactive class 11 chemistry CBSE
![arrow-right](/cdn/images/seo-templates/arrow-right.png)
Let X and Y be the sets of all positive divisors of class 11 maths CBSE
![arrow-right](/cdn/images/seo-templates/arrow-right.png)
Let x and y be 2 real numbers which satisfy the equations class 11 maths CBSE
![arrow-right](/cdn/images/seo-templates/arrow-right.png)
Let x 4log 2sqrt 9k 1 + 7 and y dfrac132log 2sqrt5 class 11 maths CBSE
![arrow-right](/cdn/images/seo-templates/arrow-right.png)
Let x22ax+b20 and x22bx+a20 be two equations Then the class 11 maths CBSE
![arrow-right](/cdn/images/seo-templates/arrow-right.png)
Trending doubts
Fill the blanks with the suitable prepositions 1 The class 9 english CBSE
![arrow-right](/cdn/images/seo-templates/arrow-right.png)
At which age domestication of animals started A Neolithic class 11 social science CBSE
![arrow-right](/cdn/images/seo-templates/arrow-right.png)
Which are the Top 10 Largest Countries of the World?
![arrow-right](/cdn/images/seo-templates/arrow-right.png)
Give 10 examples for herbs , shrubs , climbers , creepers
![arrow-right](/cdn/images/seo-templates/arrow-right.png)
Difference between Prokaryotic cell and Eukaryotic class 11 biology CBSE
![arrow-right](/cdn/images/seo-templates/arrow-right.png)
Difference Between Plant Cell and Animal Cell
![arrow-right](/cdn/images/seo-templates/arrow-right.png)
Write a letter to the principal requesting him to grant class 10 english CBSE
![arrow-right](/cdn/images/seo-templates/arrow-right.png)
Change the following sentences into negative and interrogative class 10 english CBSE
![arrow-right](/cdn/images/seo-templates/arrow-right.png)
Fill in the blanks A 1 lakh ten thousand B 1 million class 9 maths CBSE
![arrow-right](/cdn/images/seo-templates/arrow-right.png)