Question

What is the correct unit of concentration for the following solution?

$0.5moles$ of $Ca{Cl}_2$ dissolved in $0.25kg$ of water.

[Note : All the symbols are in their standard form]

• A. $w/w$
• B. $m$
• C. $M$
• D. $v/v$

Answer 1

Answer: (B)

$m$

Molality (m) of a substance is defined as the ratio of number of moles of solute and weight of solvent in Kg.

Here, molality $=\frac{0.5}{0.25}=2m$

So, the unit of molality is "m".

Hence, option (B) is correct.