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J

Jspake

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MERIHAN said:
when i asked my teacher abt this question , she said sometime cie confuse ppl ! so you know that sodium hydroxide , hydrogen and sodium cannot form at anode . only chlorine can form so A seems to be correct !! as far as sodium hydroxide is concerned we studied it is nt form at cathode but remember sometime in paper 6 of chem they are asking why the universal indicator turn purple at cathode and the answer is bcuz of sodium hydroxide not hydrogen !!! THEY MIGHT CONFUSE YOU BUT ALWAYS SEE FOR THE OPTION YOU ARE SURE OF LIKE A .

HOPE IT HELPED YOU :)
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Oh okay.. thanks a lot!
 
GorgeousEyes

GorgeousEyes

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Jun03 , No.21
Jun00 ,No.8
Jun00,33
Nov01,no.3
Jun08 ,no.19
Jun09 ,no.17
Jun010 ,no.26

please some1 explain them (A) thanks
 
A

Ahmed Khider

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GorgeousEyes said:
Jun03 , No.21
Jun00 ,No.8
Jun00,33
Nov01,no.3
Jun08 ,no.19
Jun09 ,no.17
Jun010 ,no.26

please some1 explain them (A) thanks
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In jun00 qno 8..U knw that water is neutral so the ph in the end must be either A or B. Dilute sulphuric acid cannot be changed to a ph of 7 or more thatn 7 unless you use a strong base like NAOH so the answer is B.
In JUN00 qno 33 it is a rule that when u add an ammonium salt to a base ammonia is given out and ammonia turns litmus paper blue so the answer is A.
I dnt have Nov01 :/.
In Jun08 no 19, the best way to explain it is to look at the name before and after the reaction..the name still says
chromate(
VI) indicating that the chromate ions charge remains the same so the ans is either C or D. Then at the beginning of the question it says that excess NAOH was added and NAOH is a strong alkali(i.e soluble in water) so it will increase the pH of the mixture.
In jun09 qno 17..As u can c the forward reaction is breaking down a compund(liquid) by heating and so reversing it would be by adding water(cooling) and so the answer is B..and btw this is a test for water.
In jun2010 question no 26..for a reaction to occur in this question a reactive halogen should displace a less reactive halid from its compund. In group 7 the reactivity increases upwards and so the only choice where a reaction would occur is D becoz chlorine can displace iodide ions from their compunds being more reactive than them.
 
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