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# Working with molarity/molality

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35) which if any of the following species are in the greatest c in a 0.100 molar solution Hsub2SOsub4 in water?
a) Hsub2SOsub4 molecules
b) Hsub3O^+ ions
c) HSOsub4^- ions
d) SOsub4^2- ions
e) all species are in equillibrium and thus the same concentration.

36) at 20 degrees C the vapor pressure of toluene is 22mm Hg and that of benzene is 75 mm Hg. An ideal solution, equimolar in toluene and and benzene is prepared. And 20 degree C what is the mole fraction of benzene in the vapor in equilibrium with the solution?

https://brainmass.com/chemistry/acids-and-bases/working-molarity-molality-14995

## SOLUTION This solution is FREE courtesy of BrainMass!

35) which if any of the following species are in the greatest c in a 0.100 molar solution Hsub2SOsub4 in water?

H2SO4 ionizes completely in water as,

H2SO4 aq --> H3O+ + SO4 ^2-
H2SO4 is Diprotic - a solution that produces two moles of H+ ions per mole of acid.

Thus the answer is b) Hsub3O^+ ions

36.Use Raoult's law to find the vapor pressures of the two species

Pbz = Xbz * P*bz and
Pto = Xto * P*to
(X is the mole fraction and P* denotes the vapour pressure of pure component)

In our case, let's take Xbz = Xto = 0.5 (both Benzen and toluene 50%)
Now,

Pbz = 0.5 * P*bz = 0.5*75 = 37.5mm

Pto = 0.5 * P*to = 0.5 * 22 = 11mm

Ptotal = 37.5+11 = 48.5mm

Now X benzene = 37.5/48.5 = 0.775 --Answer

This content was COPIED from BrainMass.com - View the original, and get the already-completed solution here!