How was Chemistry P1/2

[hopy12345]

can any one tell the method of preparation of copper chloride??
n the salt formed in flue gasses ques??

 

[Ali_00921]

what was the concentration for Potassium Hydroxide?
And what is balanced equation for sulphuric acid and potassium hydroxide?

 

[UziB]

people u have got it wrong..!!
in the electrolysis ques of aq cuso4 the answer was oxygen always forms at anode..!! the sulfate statement was sulphate ions rush towards the anode...n its absolutely not correct..!!

Wrong, that is not necessary. They did not specify which electrodes we were using. If we would have been using copper electrodes, then nothing would have been formed at the anode, not even oxygen hence the answer is still A, copper always forms at the cathode.

 

[UziB]

can any one tell the method of preparation of copper chloride??
n the salt formed in flue gasses ques??

Copper(I) Chloride or Copper(II) Chloride? Copper(I) Chloride is an insoluble salt while Copper(II) Chloride is soluble so it depends.
And the salts formed could have been either Calcium Nitride or Calcium Nitrate. Both are correct.

 

[UziB]

will i get a single mark for writing use dil. hcl for the formation of methanoic acid??

Yes you will, since that indicates the presence of acidic conditions which is correct.

 

[UziB]

what was the concentration for Potassium Hydroxide?
And what is balanced equation for sulphuric acid and potassium hydroxide?

0.083 mol/dm3.
2KOH + H2SO4 -> K2SO4 + 2H2O

 

[madara]

and wat about graphite????

 

[beeloooo]

The lamp MCQ's answer was liquid mercury, since the mercury never discharges at the electrodes it will cause the lamp to light up dimly. Its similar to a past paper MCQ, they just changed the approach.
In p2, titration question we had to take 30cm3 as the volume since that was the amount neutralizing the acid. I think the concentration was 0.083 as beeloooo said.
In the electrolysis of Copper(II) Sulfate the Cu2+ ions are ALWAYS attracted towards the negative electrode no matter what the conditions, since it is lower than hydrogen. Sulfate ions are never discharged.
In the MCQ relating to Aluminium Oxide's electrolysis, the answer was that Aluminium is always formed at the cathode and Carbon Dioxide/Monoxide is always formed at the anode since the oxygen that is deposited corrodes away the carbon electrode by reacting with it.
Silver Nitrate was the answer for the MCQ regarding how to differentiate between HCl and HNO3 since a white precipitate of Silver Chloride will be formed in that case.

I second each and every thing u wrote !!ditto lyk mines

 

[beeloooo]

people u have got it wrong..!!
in the electrolysis ques of aq cuso4 the answer was oxygen always forms at anode..!! the sulfate statement was sulphate ions rush towards the anode...n its absolutely not correct..!!

lol i love ur confidence the way u easily wrote the wrong answer as correct !!

 

[M Haseeb Javed]

h0w d0es the percentile system actually w0rk?...like if it bec0mes l0w, can a A turn int0 an A*?.....like can v really rely 0n percentile?

I think we cant! Cuz it was our paper that will give us result!

 

[theViperace]

lol the answer was definitely Mercury. No doubt in that.

Yeah , Mercury is right. Graphite is a very good electrical conductor so lamp will always light. Mercury is a very weak electrolyte

 

[M Haseeb Javed]

I second each and every thing u wrote !!ditto lyk mines

Mercury is a Transition metal so its conduction is very good. Ref>Wikipedia

 

[Ahmedfj]

Do one thing guys jus write on google about mercury in electrolysis !! u;ll be sure that it is a weak electrolyte !!!and option D is 100 % ryt

mercury is not an electrolyte bhai coz its a metal .. electrolytes are salt solutions

 

[theViperace]

lol i love ur confidence the way u easily wrote the wrong answer as correct !!

Past Paper question. I think it was in the 99 paper and yeah i went for B. I walked outside the center and my friend told me that its A , he is a very good student , best amongst us and i was like what the heck. Then another of my friend called me and said that it was the oxygen one , I am still confused

 

[UziB]

Can anyone tell me the answer to that MCQ in which they had asked as to why the following organic compound's melting/boiling point is higher than the previous organic compound's one? (cant remember the names)
Was it because more covalent bonds have to be broken or because the forces of attraction between the atoms increase?

 

[theViperace]

mercury is not an electrolyte bhai coz its a metal .. electrolytes are salt solutions

Zaruri nahi hein,.,. what about the bases and alkalis

 

[Ahmedfj]

Zaruri nahi hein,.,. what about the bases and alkalis

yeah them too but metals in molten form are not electrolytes coz its the property of electrolytes that they get chemically changed after electricity is passed through them .. jubke metals mai koi change hota he nahi

 

[theViperace]

paper2 wasn't that much difficult but the only thing is .......time was very short!!!!!!

Spot on,..,., time was very short. I thought k it was of 1 hr 45 mins plus light went out at the centre for around 15 mins

 

[bikermicefrmars]

Can anyone tell me the answer to that MCQ in which they had asked as to why the following organic compound's melting/boiling point is higher than the previous organic compound's one? (cant remember the names)
Was it because more covalent bonds have to be broken or because the forces of attraction between the atoms increase?

More covalent bonds have to be broken!

 

[madara]

........

Yes you will, since that indicates the presence of acidic conditions which is correct.

hey for the methanoic acid one.........i wrote react in air.......with acidified potassium dichromate......is that good enough for 2 marks