Question

Assertion :The molality and molarity of dilute aqueous solutions differ very little.
Reason: The density of water is $1.0gc{m}^{-3}$ at room temperature.

• A. Both Assertion and Reason are correct and Reason is the correct explanation for Assertion
• B. Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion
• C. Assertion is correct but Reason is incorrect
• D. Assertion is incorrect but Reason is correct

Answer 1

The correct option is A Both Assertion and Reason are correct and Reason is the correct explanation for Assertion

$\text{Molarity}=\frac{\text{Number of moles of solute}}{\text{Volume of solution in L}}$
$\text{Molality}=\frac{\text{Number of moles of solute}}{\text{Mass of solvent in kg}}$
The molality and molarity of dilute aqueous solutions differ very little because the density of water is $1.0gc{m}^{-3}$ at room temperature. Due to this, the volume of solution will be approximately equal to the mass of solvent.
Thus, both Assertion and Reason are correct and Reason is the correct explanation for Assertion.