Question

Assertion : One molar aqueous solution is more concentrated than that of $1$ molal aqueous solution.
Reason : Molarity is a function of temperature as volume depends on temperature.

• A. If both assertion and reason are true and reason is the correct explanation of assertion
• B. If both assertion and reason are true but reason is not the correct explanation of assertion
• C. If assertion is true but reason is false
• D. If both assertion and reason are false

Answer 1

Answer: (B)

$1$ molar solution has $1$ mole of solute per litre of solution or per $1000\, cm^3$ of solution.
Now, density of water $= 1\, g/cc$
$\therefore 1000\, cm^3 = 1000\, g$
Hence, $1$ mole is present in less than $1000 \,g$ of solvent
$[\because 1000 \,g$ of solution = solute and solvent]
Whereas $1$ molal solution has $1$ mole of solute in $1000 \,g$ of solvent.