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Chemistry: Post your doubts here!

qwertypoiu

qwertypoiu

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Eugene99 said:
How does, acidifying the pool water, not let the OCl to break down?View attachment 59887
Click to expand...
The question says how to keep concentration of HOCl to maximum.
The equilibrium is:

OCl- + H2O <---> OH- + HOCl

Whichever of the choices keeps the above equilibrium shifted to the right is the correct answer.

Adding the acid will remove OH- ions and thus shift equilibrium to the right, so it is the correct answer.
 
Eugene99

Eugene99

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qwertypoiu said:
The question says how to keep concentration of HOCl to maximum.
The equilibrium is:

OCl- + H2O <---> OH- + HOCl

Whichever of the choices keeps the above equilibrium shifted to the right is the correct answer.

Adding the acid will remove OH- ions and thus shift equilibrium to the right, so it is the correct answer.
Click to expand...
oh right! thank you :)
 
The Sarcastic Retard

The Sarcastic Retard

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How to determine the common oxidation states of transition elements?
I am heck confused. I have seen questions asking valencies. So any help?
 
Mohammed Elatta

Mohammed Elatta

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The Sarcastic Retard said:
How to determine the common oxidation states of transition elements?
I am heck confused. I have seen questions asking valencies. So any help?
Click to expand...
Most common oxidation state is +2 but the transition elements at the start of the row oxidation state involves all of the electrons present in the 4s and 3d subshells , however from iron onwards the maximum oxidation state becomes +2 since the 3d electrons become relatively harder to remove. for example vanadium which is a transition element at the start of the row can have all of its electrons removed from the 4s and 3d subshell therefore can be +1 . +2 , +3 , +4 and even +5. I might be mistaken correct me if i'm wrong though.
 
cute97

cute97

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Saad the Paki said:
I'm not quite sure it's either 31 or 32 but I haven't received my statement of entry yet so I don't know for sure.
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Oh okay, our school gave it already, I will be doing v31, when you come to know when is your practicals and which variant please tell me :) Where do you live?
 
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Rizwan Javed

Rizwan Javed

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Eugene99 said:
View attachment 59902
How do I know which one is a redox reaction? (Ans is B)
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Option A shows a simple dehydration or elimination reaction. No change in oxidation takes places.

Option C is the hydrolysis of esters. Again no change in oxidation states.

Option D: The reaction does not take place, as ketones do not react with fehling's solution.

Only Option B shows a redox reaction as in this reaction the aldehyde is oxidised to form carboylic acid, and the Ag+1 ions present in the tollen's reagent are reduced to form Ag(s). So as both oxidation and reduction take place, this is the only redox reaction.
 
The Sarcastic Retard

The Sarcastic Retard

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Mohammed Elatta said:
Most common oxidation state is +2 but the transition elements at the start of the row oxidation state involves all of the electrons present in the 4s and 3d subshells , however from iron onwards the maximum oxidation state becomes +2 since the 3d electrons become relatively harder to remove. for example vanadium which is a transition element at the start of the row can have all of its electrons removed from the 4s and 3d subshell therefore can be +1 . +2 , +3 , +4 and even +5. I might be mistaken correct me if i'm wrong though.
Click to expand...
Ty. I d k if u are wrong coz I have got nothing to be frank. :p
 
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