Question

Two aqueous solutions are prepared: 1.00 m Na2CO3 and 1.00 m LiCl. Which of the following statements is true?

Answer 1

Answer:

The $Na_{2}CO_{3}$ solution has a higher osmotic pressure and higher boiling point than LiCl solution.

Explanation:

As concentrations of two aqueous solutions are same therefore we can write:

                                $\Delta P\propto i$ , $\Delta T_{b}\propto i$ and $\pi \propto i$

where $\Delta P$, $\Delta T_{b}$ and $\pi$ are lowering of vapor pressure, elevation in boiling point and osmotic pressure of solution respectively. $i$ is van't hoff factor.

$i$ = total number of ions generated from dissolution of one molecule of a substance (for strong electrolyte).

Here both $Na_{2}CO_{3}$ and LiCl are strong electrolytes.

So, $i(Na_{2}CO_{3})=3$ and $i(LiCl)=2$

Hence, lowering of vapor pressure, elevation in boiling point and osmotic pressure will be higher for $Na_{2}CO_{3}$ solution.

Therefore the $Na_{2}CO_{3}$ solution has a higher osmotic pressure and higher boiling point than LiCl solution.