Question

Statement 1: The molality and molarity of very dilute aqueous solutions differ very little.
Statement 2 : The density of water is about $1.0\, g \,cm^{-3}$ at room temperature.

• A. If both Statement $1$ and Statement $2$ are true and the statement $2$ is the correct explanation of the statement $1$
• B. If both Statement $1$ and Statement $2$ are true but statement $2$ is not the correct explanation of the statement $1$
• C. If Statement $1$ is true but Statement $2$ is false
• D. If Statement $1$ is false but Statement $2$ is true

Answer 1

Answer: (A)

Molarity $=\frac{\text { Number of moles of solute }}{\text { Volume of solution in L} }$
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 $1.0\, g\, cm ^{-3}$ 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.