• # question_answer 20) If the density of methanol is $0.793\,\,kg\,\,{{L}^{-1}}$. What is its volume needed for making 2.5L of its 0.25M solution?

Answer:

We know, $M=\frac{{{w}_{B}}\times 1000}{{{m}_{B}}\times V}\,\,\,\,\,\,\,\,\,\,\,\,......(i)$ Given : M = 0.25 g, V = 2.5L = 2500 mL, ${{m}_{B}}$ (molar mass of $C{{H}_{3}}OH$) = 32 g $mo{{l}^{-1}}$ Putting these values in Eqn. (i), we get $0.25=\frac{{{w}_{B}}\times 1000}{32\times 2500}$ ${{w}_{B}}=20g$ Volume of solute = $\frac{Mass}{Density}=\frac{20}{0.793}$ = 25.22 mL (Here, density = $0.793kg\,{{L}^{-1}}$ or 0.793 g $0.793g\,m{{L}^{-1}}$)

You need to login to perform this action.
You will be redirected in 3 sec