Question

Which of the following aqueous solutions will have the lowest vapor pressure at 25°C?

1.0 M Fe(NO3)3
2.0 M C6H12O6
1.0 M KNO3
2.0 M CaCl2

Answer 1

@Abhisar how would i determine this?

Answer 2

I am not sure about this one but i think it has something to do with number of particles.

Answer 3

oh. it is okay!

Answer 4

Vapour pressure lowering is a colligative property, one that depends on the number, rather than identity, of dissolved solutes. Dissolved solutes lower the vapour pressure of a liquid since they interfere with the conversion of liquid to gas at the liquid-gas interface. Therefore, the more dissolved solutes you have (i.e. the greater the concentration), the lower the vapour pressure is since the transition from liquid to gas is more obstructed.

Answer 5

C6H12O6 is glucose (or several other sugars, doesn't really matter), which does not dissociate into additional ions when dissolved. Therefore 2 M C6H12O6 produces 2 M of solute.



CaCl2 dissociates into Ca2+ and 2 Cl- when dissolved, so every mole of 1.0 M CaCl2 produces 3 moles of dissolved solute. Therefore, 2.0 M CaCl2 produces 6 M of solute.

Answer 6

ah then i am thinking it would be 2.0 M CaCl2

Answer 7

really?

Answer 8

oh wait yep i see now!

Answer 9

thank you!

Answer 10

`Substance which will produce most amount of solute particle will have the least vapor pressure`

Answer 11

\(\color{blue}{\text{Originally Posted by}}\) @superhelp101
ah then i am thinking it would be 2.0 M CaCl2 \(\huge\checkmark\)
\(\color{blue}{\text{End of Quote}}\)

Answer 12

wheee!:)

Answer 13

\(\huge\sf\color{green}{\text{✌ﾟ\(\ddot\smile\) ✌ﾟ}}\)