Some Basic Concepts of Chemistry - Result Question 40
Interger Answer Type Questions
41. A compound $\mathrm{H}_2 \mathrm{X}$ with molar weight of 80 g is dissolved in a solvent having density of $0.4 \mathrm{~g} \mathrm{~mL}^{-1}$. Assuming no change in volume upon dissolution, the molality of a 3.2 molar solution is
(2014 Adv.)
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Answer:
Correct Answer: 40. (8)
Solution:
- PLAN This problem can be solved by using concept of conversion of molarity into molality. Molarity $=3.2 \mathrm{M}$ Let volume of solution $=1000 \mathrm{~mL}=$ Volume of solvent
$\text { Mass of solvent }=1000 \times 0.4=400 \mathrm{~g}$
Since, molarity of solution is 3.2 molar
$\begin{aligned} & \therefore \quad n_{\text {solute }}=3.2 \mathrm{~mol} \\ & \text { Molality }(m)=\frac{3.2}{400 / 1000}=8 \\ \end{aligned}$
Hence, correct integer is (8).
BETA
