Chemistry Help needed!:-(

[Christy]

electrolysis of concentrated sodium chloride using carbon electrodes
the solution also contained litmus solution

What happened to the colour of solution around cathode
Why did this change take place?

If there is hydorgen produced at the cathode
then why would there be a colour change since hydrogen is a neutral gas...shouldnt it stay green?
I dont get it...

Chlorine and hydrogen leaves .. NaOH is left in the solution turning theu niversal indicator blue cause its a base and chlorine bleaches

[twilight]

you are wrong twilight in electrolysis the cation which is lower in the reactivity series i.e. hydrogen

concentration only effects which anion goes i.e. chlorine

when chlorine and hydrogen leave sodium hydroxide is left behind which is a base so litmus indicator turns blue.

sorry .  my wrong

[Naruto]

Guyz plzz help me out with the last question of chemistry paper6 Nov 2000
plzzzz explain the full answer because it is of 6 marks...and tell me this question is from which topic?

i have attached the link
Thanks

[astarmathsandphysics]

Would it simply be that no more is formed?


I know nothing about chenistry but I find exam questions very predictable.

[Naruto]

ummm...astar are you answering my question
its the question no. 6 on the last page...about calcium carbonate
i think you checked the wrong question...but its ok you can check and tell me if you knw the answer.
thanks

[astarmathsandphysics]

ummm...astar are you answering my question
its the question no. 6 on the last page...about calcium carbonate
i think you checked the wrong question...but its ok you can check and tell me if you knw the answer.
thankshttp://www.mozdev.org/

My browser is behaving strangely but are you saying?

Calcium carbonate is found in egg shells. All carbonates react with hydrochloric acid to form
chlorides. Calcium carbonate is insoluble in water but calcium chloride is soluble. Most impurities
in egg shells are insoluble. Plan an experiment to find out if egg shells are 100% calcium
carbonate.

[twilight]

k i think u havta put the eggshells in HCl (CaCO₃ will react to give CaCl₂).. after the reaction .. add water to dissolve the CaCl₂ that is formed .. and filter the mixture .. if there is any residue in the filter paper then the eggsells are not 100% .. as only CaCl₂ dissolves in water

[Naruto]

@ astar
yeah i am asking for that question

@ twilight
Thanks for your answer

[hyebyekadal]

Ok need help winter 2005 IGCSE
5 A solid compound X was analysed. Solid X was an aluminium salt. The tests on X and
some of the observations are in the following table.
Complete the observations in the table.
(a) One spatula measure of X was
placed into a hard-glass testtube.
The solid was heated
gently then strongly. The gas
was tested with pH indicator
paper. paper went red

 ms sayss acidic gas/hydrated
and the theres a quesiton about the the substance x and the ms again says a hydrated salt.
if its a hydrated salt then why acidic gas forming?

[Christy]

there must be something mentioned above in the question so that they can say hydrated ... maybe it was heated and it gave out h20 vapours ...

the answer is hydrated acid salt ... i think

[godfather93]

here's a link through which anyone can learn the anion and cation tests easily.
http://library.thinkquest.org/2923/tests.html

[hyebyekadal]

this is whole q!

[Pharoah]

 

5 A solid compound X was analysed. Solid X was an aluminium salt. The tests on X and
some of the observations are in the following table.
Complete the observations in the table.
(a) One spatula measure of X was
placed into a hard-glass testtube.
The solid was heated
gently then strongly. The gas
was tested with pH indicator
paper. paper went red

The salt was probably aluminum carbonate which decomposed on heating to aluminum oxide and carbon dioxide. Carbon dioxide is acidic so the litmus turned red.

[hyebyekadal]

o no i thought of that also but the later in the question u find out its nitrate and there NO mention of carbonate thats what i wrote! I said that there were carbonates impurities.. but the only answer the ms provided is hydrated salt!

[Pharoah]

Why don't you post the entire question. maybe we could help you better then.