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CHEMISTRY PAPER 1 HERE

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john12345:

--- Quote from: Tammy on June 10, 2009, 02:39:13 pm ---Yes, hydrogen is produced at the negative electrode, but if you look at the solution left: it's NaOH which is basic.

   Na+         Cl-
   H+          OH-

The ones coloured red are the ones that are produced at the electrodes, and what's left is Sodium hydroxide.

--- End quote ---
hey tammy thanks a lot for ur help

i had one more doubt about this
why is the sodium hyroxide formed at the cathode, shudnt it just form anywhere in the tube

y is it specifically formed at the cathode?????

nd shudnt de hydrogen formed at the cathode make the cathode area acidic>????

esso:
NaOH form at the cathode cause the formula is :

2H2O+2e=h2+2OH-

THERFORE HYDROXIDE IONS FORM NEAR THE CATHODE .....
THIS HYDROXIDE IONS MAKE THE INDICATOR COLOUR GOES BLUE....


hope i helped.... :)

john12345:

--- Quote from: esso on June 10, 2009, 03:10:32 pm ---NaOH form at the cathode cause the formula is :

2H2O+2e=h2+2OH-

THERFORE HYDROXIDE IONS FORM NEAR THE CATHODE .....
THIS HYDROXIDE IONS MAKE THE INDICATOR COLOUR GOES BLUE....


hope i helped.... :)

--- End quote ---

hey esso
but since de hydroxide ions are negatively charged shudnt dey be attracted to the positive electrode (anode)
nd how does water gain 2 electrons, where does it get dose 2 electrons from ????

im slightly confused

i understand dat oxidation taked place at the anode with clhorine ions losing electrons to form chlroine gas

and dat reduction takes place at cathode with hydrogen ions gaining electrons from de cathode to form hydrogen gas

den what happens to the remaining sodium ions nd hydroxide ions

how come they form near the cathode???

esso:
since the hydroxide ions form near the cathode .... they attract the sodium ions and form at the cathode.....

.....dont have to know in detail though....

water gains electrons from the cathode ,,, therefore reduction takes place as u said .....

john12345:

--- Quote from: esso on June 10, 2009, 03:24:53 pm ---since the hydroxide ions form near the cathode .... they attract the sodium ions and form at the cathode.....

.....dont have to know in detail though....

water gains electrons from the cathode ,,, therefore reduction takes place as u said .....

--- End quote ---

thanks a lot esso
+ rep for u
however dude i dont get it why do de hydroxide ions form near the cathode shudnt dey be attracted to de anode dats wat i dont undersatdn
i understand dat sodium ions are formed near de cathode since dey are attracted to the cathode as they are positive ions

nd dude y does water gain 2 electrons to form hydroxide
shudnt water naturally dissociate to form the hydrogen ions and hydroxide ions

because we have never been taught about water gaining 2 electrons from de cathode to form de hydroxde ions + hydrogen

we have been told dat water dissociates to produce hydrogen ions _ hydroxide ions

nd for hydroxide weve learnt that

4OH- = 2H20 + O2 + 4 electrons

can u please help as to why water gains two electrons from the cathode?????????/

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