Molality And Molarity

The molarity (M) is given by:

M%20%3D%20%5Cfrac%7B%5Ctext%7Bmoles%20of%20solute%7D%7D%7B%5Ctext%7Bvolume%20of%20solution%20in%20liters%7D%7D

The number of moles of CaCl

_2

is calculated as:

%5Ctext%7BMoles%20of%20CaCl%7D_2%20%3D%20%5Cfrac%7B%5Ctext%7BMass%7D%7D%7B%5Ctext%7BMolar%20mass%7D%7D%20%3D%20%5Cfrac%7B22.2%20%5C%2C%20%5Ctext%7Bg%7D%7D%7B147%20%5C%2C%20%5Ctext%7Bg%2Fmol%7D%7D%20%3D%200.15%20%5C%2C%20%5Ctext%7Bmol%7D

Thus, the molarity is:

M%20%3D%20%5Cfrac%7B0.15%7D%7B1%7D%20%3D%200.15%20%5C%2C%20%5Ctext%7BM%7D%20%5Cquad%20(%5Ctext%7Bapprox%7D%200.2%20%5C%2C%20%5Ctext%7BM%7D%20%5Ctext%7B%20for%20the%20closest%20match%20to%20the%20options%7D).

Thus, the correct answer is Option (A).

To calculate the molality (

m

) of the sulphuric acid, we can use the formula:

m%20%3D%20%5Cfrac%7Bn_%7B%5Ctext%7Bsolute%7D%7D%7D%7Bm_%7B%5Ctext%7Bsolvent%7D%7D%7D

Where: -

n_%7B%5Ctext%7Bsolute%7D%7D

is the number of moles of solute, -

m_%7B%5Ctext%7Bsolvent%7D%7D

is the mass of the solvent in kilograms. We are given: - The molarity (

M

) of the solution is 4.5 M, which means 4.5 moles of H

_2

_4

are present in 1 liter of solution. - The density (

%5Crho

) of the solution is 1.28 g/ml, which is equivalent to 1280 g/L. The mass of the solution is:

%5Ctext%7Bmass%20of%20solution%7D%20%3D%201280%20%5C%2C%20%5Ctext%7Bg%2FL%7D

The mass of the solute (H

_2

_4

) is:

%5Ctext%7Bmass%20of%20solute%7D%20%3D%204.5%20%5C%2C%20%5Ctext%7Bmol%2FL%7D%20%5Ctimes%2098%20%5C%2C%20%5Ctext%7Bg%2Fmol%7D%20%3D%20441%20%5C%2C%20%5Ctext%7Bg%7D

The mass of the solvent (water) is:

%5Ctext%7Bmass%20of%20solvent%7D%20%3D%201280%20%5C%2C%20%5Ctext%7Bg%7D%20-%20441%20%5C%2C%20%5Ctext%7Bg%7D%20%3D%20839%20%5C%2C%20%5Ctext%7Bg%7D%20%3D%200.839%20%5C%2C%20%5Ctext%7Bkg%7D

Now, we can calculate the molality (

m

m%20%3D%20%5Cfrac%7B4.5%20%5C%2C%20%5Ctext%7Bmol%7D%7D%7B0.839%20%5C%2C%20%5Ctext%7Bkg%7D%7D%20%3D%205.364%20%5C%2C%20%5Ctext%7Bmol%2Fkg%7D

Thus, the molality of the acid is 5.364 mol/kg.

About Molality And Molarity - COMEDK-UGET

Molality And Molarity is a vital chapter for COMEDK-UGET aspirants. Mastering the concepts covered in this chapter is essential for securing a top rank.

By rigorously practicing the previous year questions associated with this chapter, you can identify high-yield topics, understand the examiner's perspective, and boost your confidence during the actual exam.

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Analyzing PYQs for this specific chapter reveals the most frequently tested concepts and the typical complexity of questions, allowing you to tailor your study plan efficiently.

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Review the topic breakdown to see which sub-topics within Molality And Molarity carry the most weight. Then, tackle the questions iteratively to solidify your understanding.

High-Yield Trend

Chapter Questions
2 MCQs

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About Molality And Molarity - COMEDK-UGET

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Why focus on Molality And Molarity PYQs?

How to best use this analysis?

Molality And Molarity

High-Yield Trend

Chapter Questions 2 MCQs

Official Solution

Official Solution

About Molality And Molarity - COMEDK-UGET

Frequently Asked Questions

Why focus on Molality And Molarity PYQs?

How to best use this analysis?

Chapter Questions
2 MCQs