Chemistry O/N 09

[Kokeeto]

http://www.xtremepapers.me/CIE/index.ph ... _qp_11.pdf
Hey guys, hope everyone is studying well.
Please check number 13, I really don't understand why the answer is D...
I know that chlorine is formed at the anode, and it is an acidic gas, so the colour will be red.
And for the cathode, hydrogen is made....

 

[xIshtar]

Chlorine isn't acidic, it bleaches all indicators white or off-yellow..

The answer is D because the indicator at the anode is colourless, and the indicator at the anode turns blue/purple as NaOH is formed, due to the removal of H at the cathode.

Hope I helped, best of luck tomorrow

 

[Kokeeto]

Thanks a lot,but doesn't the universal indcator at the cathode test what is formed at the cathode (which is hydrogen), and I guess hydrogen isn't acidic nor basic, thx a lot, and same to u

 

[CaptainDanger]

Chlorine is going out.... The indicator is in the solution... So it won't turn red... It will be colorless... At cathode when Hydrogen is released the solution will be left with OH ions... So due to OH ions it will turn blue or purple... So the answer is D...

 

[Kokeeto]

Thx
Gd luck

 

[CaptainDanger]

Thanks a lot,but doesn't the universal indcator at the cathode test what is formed at the cathode (which is hydrogen), and I guess hydrogen isn't acidic nor basic, thx a lot, and same to u

You are right... But as I mentioned... The indicator is in the solution not at the TOP of the tube....