KBT exam help!

[crayolé]

Lovely exam, wouldn't mind something like this for tomorrow 

Nice solutions, I got these questions wrong and not sure why

For MC 18 - If X and Y were joined, they say there will be no reaction because of the lack of a salt bridge. But both cells are connected to a salt bridge which I'm sure would be more than willing to donate their preciouss ions? So wouldn't neutrality still technically be maintained?

For question 1c.
They've used the original concentration for the denominator in K_b
Should the highlighted value [.035M] include the loss in concentration of the [CH₃NH₂] upon ionization?

Cheers

[samiira]

When the electric current flows through the wire, electrons are transported through the wire from one half-cell (oxidation side, anode) to the other half-cell (reduction side, cathode). This leaves a
deficiency of negative charge (surplus of positive charge) on the anode side and produces a surplus of negative charge on the cathode side. When the electric current flows through the wire, electrons are transported through the wire from one half-cell (oxidation side, anode) to the other half-cell (reduction side, cathode). This leaves a deficiency of negative charge on the anode side and produces a deficiency of positive charge on the cathode side.

With ur question, the X and the Y  have to be connected to the one salt bridge.. if ur trying to say why cant they get it from their own salt bridge in their own cell, well u cant because X is undergoing reduction in its own cell and the Y also undergoes reduction in its own cell aswell so it wont work out.

With Q1c. I wudnt recommend u think too deeply about that sorta stuff... I just worked it out straightforward and got the answer.

[crayolé]

Thanks for your help but what do you mean both cells are undergoing reduction? They're both fit for a spontaneous reaction :/

[Martoman]

no. as with all weak acid questions, you assume the ionisation is small so concentration doesn't really change.

[crayolé]

Thanks <3
What about for the first question, any idea on that one?

[Martoman]

Samiira said it right. They are connected but no way to balance the charge, polarization will occur.