NO2 question from chemical eqb in 11th class. the question was easy but the calculations were crazy. conc of No2 was 12.6x10^-4 (this is my ans don't know about the correct ans)
The no2 question... N2 + O2 = 2NO .8-X .2-X 2X k=2X*2X/(.8-X)(.2-X)=1/100000 SOLVING WE GET THE ANSWER APPROXIMATELY .63/1000 X=.63/100000 2X=1.26/100000
everyone taking about N + O2 ----> NO2 I WOULD LIKE TO TELL IT WAS CLASS 11 QUESTION...PRETTY EASY..!!HOWEVER OUT OF SYLLABUS..SO MAY GET FULL MARKS IN THAT..!!
it wasn't much tough as expected.. only, dat kinetics question broke a nerve.. else, it wos fyn..guys, its out of sylabus rite? sure of grace marks? and der wer few qstns dat wer out of the CBSE published curriculum..mainly the structure of oxide of nitrogen..
It was easier as compared to physics. 1 question was out of syllabus(c.equilibrium) but i was able to attempt it. But this year paper is not comparable with previous year papers. Paper was not lenghty at all and was 80% medium level.
Yeah it was easy for all including me,,but i got to tell every ' THE HINDU ' newspaper reader who studied according to the responses about the syllabus for CBSE 2012 Board exam given by the CBSE authorities on request in " ASK CBSE " section of 'Education PLus', a supplement of THE Hindu, even though they had clearly said that Catalysis,Ideal Solutions and some other,topics are not included. But For the board exam,questions came for the board exam from these excluded topics. So i request plustwophysics administrators to give the marks to all for all the questions out of syllabus,,as students through The Hindu had contacted Cbse authorities and clarified again and again that those topics are not really there.
Br2 will attack only the double bond. no effect on triple bond. so, you will get a vic di halide .
The answer is : 4,5-dibromopent-1-yne
do you have to balance the d block equations for full marks? pls tell. only part 2 of that qstn is a problem for me as i didn't balance it. if yes, how many marks will they deduct?
My Physics was better than chemistry......i did many silly mistakes in chem....can anyone tell what will be the answer of attack of br2 on pent4en 1yne??
well, they didn't specify how many moles of bromine...so i took one mole and i got 1,2-dibromopent-1,4-diene. since triple bond is more reactive as more energy is given out when carbon changes from sp - sp2,,,,..but ma teacher said u have to have excess and write a hexa bromo product... since they didnt speicfy, teachers said they will argue for marks as set three dint have that question..instead those lucky ppl had a nomenclature directly from textbook :(
I missed 1 question of 2 marks ( failed to see it :( ) Still expecting 90+ , How many of u frnds are preparing for the JEE ? 8 Apr is going to be the judgement day ...
chemistry paper was easy ,,,just that 11th class question was mind bogging hoping 93+,,,but what physics had done na seriosly it burnt all the aspirations ...........i dont think will be able 2 cover the spoiled %age ...
even the question on thermosetting polymers and thermoplastic polymers according to d syllabus is out of portion... so cbse pls...oderwise d credibility of the question paper makers will be....affected
Ppr easier than physics but slightly tougher than previous years, especially some 1 and 2 marks. but No2 ques was out of portion (the concept was of 11th std chapter 'equilibrium'). also questions were asked on ideal solutions and catalysis, not in syllabus this year. CBSE must award free marks for these questions.
the paper was nice although care must have been taken not to repeat such blunders in coming years who had expected a 11th Q. to appear in a 12th AISSCE paper ? i had solved it but still its not acceptable and regarding attack of bromine, all the unsaturation will have to be made up by Br2 if Br-water is to be decolourised so the product is a hexabromo alkane
I am preparing for IIT, so level of questions never bothered me both in Physics and Chemistry. But, not going to get 70 as named that aldehyde as ketone a silly mistake to comit. I was really frustrated by that equilibrium question, solved that one correctly, but was tensed that I didn't get it correctly.
hey guys)! hav u all(iit aspirants) received jee admit cards? :/ i havent found a single person who has received it even though today z d last day..isnt it? ://
it was a very lengthy paper and not standard at all. there was too much asked in even 2 n 3 mark questions. and there was lack of numericals. and few questions were even out of main syllabus and cbse must take into account that students of outskirt schools do not have much facilities n material for study n depend solely on the ncert book. it was really disappointing. and paper should have been set for atleast 4 hours to be able to complete! its really harsh that the board wants to play with students' lives.
@anirudh..Dude paper was of appropriate length finished it in 2.5 hrs and den broke my head on that equilibrium ques.. ques of thermosetting and plastic polymers is also out of syllabus...Even the inter paper in AP was badly made...whats going on wid question paper makers???
i think physics is more easy than chem...for chem it was a medium paper...also many questions were out of syllabus.....do anybody knows the answer of organic compound-C9H10O...is it 2-ethyl benzaldehyde....
Yes, the reaction is indeed explosive, but that doesnt define an exothermic compound. An exothermic compound is one whose heat of 'formation' is exothermic, not heat of 'dissociation' Hence, the reason is that bcz of very strong bonds formed bw F nd N, the heat of formation is exo. In case of chlorine lattice energy is less so the overall energy of reaction is endo.
but i messed upwith polymer thermoseeting and thermoplastic,but i have a doubt regarding wheteher it was out of syllabus ornot..as this q is given in ncert exercise
equilibrium question is out of syllabus and structure of N2o5 is also out of syllabus but the paper is damn easy i hv completed my paper in 2hr and 45 min.
@Anirudh...I couldn't keep pace with time either. But I could have, had I not elaborated the 2 marks answers.There I made mistake in managing time.Sad that I couldn't complete writing up some answers which I knew well. Still the paper was different from the common pattern,wasn't it? Well...hoping for the best.
bio was 2222222...... gud really gud though not all sets. set 1 n 3 were really good .mine was set 3.my fnds who got set2 claimed to be togher than the other 2
I think the paper was just fine.Neither too easy nor too difficult; better than physics-as expected. Except the NO2 question- it was from class 11 syllabus. And yeah, for people who had attempted previous years' questions, it sure was cakewalk. If you were not clear about concepts, you're bound to fall flat on your face--in both physics AND chemistry. :)
che exam was not at all easy.if cbse do like this ,no one will pass in 12.nd no one will take cbse syllabus for higher secondary.this is a lesson for juniors.
The paper was much better than physics.. and i hav come thru a news frm all around that 8 marks are to be given in grace in physicz..?? for chemistry i didn't get that NO2 question..!! :/
u r right.....i think its the ques about peptisation na..........i also think that another numerical was out of syllabus too....a 3m mark ques related eqbm constant...
the numericals had complicated and lengthy sums...it ws lengthy...i hope the teachers do lenient checking..otherwise the overall percentage will be down!!
I didn't say that there will be grace marks. I said that the marking scheme is prepared in such a way as to compensate the problems with the question paper. The students who attempted the questions sincerely will get appropriate marks.
well,physics was easy but got confused in few questions.chem. was easy too...bio. contained direct n easy questions.maths was easy but 4 markers were lengthy....hope 2 secure 90+ easily in all subjects.
4 me it was quite tough....i dnt know whether i will pass.bcoz i didnt know anything.... bt i am sure dat my GOD will help me to score gud marks.. i trust in U JESUS
It was easy paper than physics,numericals were also easy,hoping biology will be easy too :)
ReplyDeleteChemistry was much Better than Physics :-) THANK U Teachers for the sake!!! & THANK U GOD...
ReplyDeleteNot really.
ReplyDeleteBetter than physics in every aspects.
the questions were easy ....much far better than physics
ReplyDeletegood paper easy.
ReplyDeleteexcept 2 question!!!!!
it was a nice paper gud questions were asked...this is how papers should be!!! but the NO2 question seemed out of portion!!!
ReplyDeletethe chemistry paper was easy...a lot better than physics. Don't know what happened to them while making the physics paper!!!
ReplyDeleteWhat about the NO2 question guys . .any idea ?
ReplyDeleteI think the NO2 question is out of portion my friends told it is from last years equilibrium chapter....hopefully grace marks!!!
ReplyDeletechemistry paper was very easy .except for 1 question on EQUILIBRIUM which was out of syllabus of 12th
ReplyDeleteNO2 question from chemical eqb in 11th class. the question was easy but the calculations were crazy.
ReplyDeleteconc of No2 was 12.6x10^-4 (this is my ans don't know about the correct ans)
The paper was quite easy compared to physics it was much better . Hope so we will do biology and maths in the same way
ReplyDeleteThe no2 question...
ReplyDeleteN2 + O2 = 2NO
.8-X .2-X 2X
k=2X*2X/(.8-X)(.2-X)=1/100000
SOLVING WE GET THE ANSWER APPROXIMATELY .63/1000
X=.63/100000
2X=1.26/100000
it was from class 11 and if u have atempt or written ques no u will get marks
ReplyDeleteAny chance of getting grace marks . . .?
ReplyDeleteI attempted it . . .
i think chemistry was much more easier than physics...
ReplyDeleteI think our physics paper correction would be liberal..Else the pass percent would be very low.
Please make sure about it.
except the equilibrium question,all were attemtavle.bt it was a bit tough than physics
ReplyDeleteeveryone taking about N + O2 ----> NO2
ReplyDeleteI WOULD LIKE TO TELL IT WAS CLASS 11 QUESTION...PRETTY EASY..!!HOWEVER OUT OF SYLLABUS..SO MAY GET FULL MARKS IN THAT..!!
wrong answer!!
ReplyDeletewat abt attack of br2 on pent4en 1yne
ReplyDeletechemistry was quite easy! :)
ReplyDelete@all
how many mrks do u guys expect???
it wasn't much tough as expected..
ReplyDeleteonly, dat kinetics question broke a nerve..
else, it wos fyn..guys, its out of sylabus rite?
sure of grace marks?
and der wer few qstns dat wer out of the CBSE published curriculum..mainly the structure of oxide of nitrogen..
It was easier as compared to physics. 1 question was out of syllabus(c.equilibrium) but i was able to attempt it. But this year paper is not comparable with previous year papers. Paper was not lenghty at all and was 80% medium level.
ReplyDelete@sunny yep, this is the right ans..
ReplyDeletehopin for grace marks.....
ReplyDeleteCBSE Chairman
ReplyDeleteVineet Joshi, IAS
Tel. 91-11-22023737, 22467263
Email: chmn-cbse@nic.in
Contact Him for that eqm que...
paper was average .the equilibrium que was very easy rather it was from 11th. some tricky que. were there. can any one explain about NF3 explosive que
ReplyDeleteYeah it was easy for all including me,,but i got to tell every ' THE HINDU ' newspaper reader who studied according to the responses about the syllabus for CBSE 2012 Board exam given by the CBSE authorities on request in " ASK CBSE " section of 'Education PLus', a supplement of THE Hindu, even though they had clearly said that Catalysis,Ideal Solutions and some other,topics are not included. But For the board exam,questions came for the board exam from these excluded topics.
ReplyDeleteSo i request plustwophysics administrators to give the marks to all for all the questions out of syllabus,,as students through The Hindu had contacted Cbse authorities and clarified again and again that those topics are not really there.
Br2 will attack only the double bond. no effect on triple bond. so, you will get a vic di halide .
ReplyDeleteThe answer is : 4,5-dibromopent-1-yne
do you have to balance the d block equations for full marks? pls tell. only part 2 of that qstn is a problem for me as i didn't balance it. if yes, how many marks will they deduct?
3 questions in 56/2 OD were out of portions.
ReplyDelete1) question 2 -> shape selective catalysis.
2) question 22 -> Equilibrium.
3) question 30 -> N205 structure.
Hope CBSE considers the matter seriously and gives 'FULL MARKS' for all those who attempted it.
tough but easier than phy.some questions were out of portion.hoping libral evaluatn for phy n chem.
ReplyDeleteMy Physics was better than chemistry......i did many silly mistakes in chem....can anyone tell what will be the answer of attack of br2 on pent4en 1yne??
ReplyDeletewell, they didn't specify how many moles of bromine...so i took one mole and i got 1,2-dibromopent-1,4-diene. since triple bond is more reactive as more energy is given out when carbon changes from sp - sp2,,,,..but ma teacher said u have to have excess and write a hexa bromo product... since they didnt speicfy, teachers said they will argue for marks as set three dint have that question..instead those lucky ppl had a nomenclature directly from textbook :(
ReplyDeleteI missed 1 question of 2 marks ( failed to see it :( )
ReplyDeleteStill expecting 90+ ,
How many of u frnds are preparing for the JEE ? 8 Apr is going to be the judgement day ...
chemistry paper was easy ,,,just that 11th class question was mind bogging hoping 93+,,,but what physics had done na seriosly it burnt all the aspirations ...........i dont think will be able 2 cover the spoiled %age ...
ReplyDeleteThe paper was easier than physics but not as easy as previous years papers. I couldn't make head or tail of the NO2 question.
ReplyDeleteeven the question on thermosetting polymers and thermoplastic polymers according to d syllabus is out of portion... so cbse pls...oderwise d credibility of the question paper makers will be....affected
ReplyDeletePpr easier than physics but slightly tougher than previous years, especially some 1 and 2 marks. but No2 ques was out of portion (the concept was of 11th std chapter 'equilibrium'). also questions were asked on ideal solutions and catalysis, not in syllabus this year. CBSE must award free marks for these questions.
ReplyDeleteWill the question from 11 syllabus(EQILIBRIUM) be considered out of syllabus for 12? If -yes, what would be the marking criterion?
ReplyDeleteWill the question from 11 syllabus(EQILIBRIUM) be considered out of syllabus for 12? If -yes, what would be the marking criterion?
ReplyDeleteReply
its 1 or 0 for the equations ...
ReplyDeleteSince nothing was mentioned, we had to take bromine in excess.. so it will become a hexa substituted product..
ReplyDeleteNo. the question is infact correct. bromine never attacks triple bond . I think, the cyclic bromonium ion intermediate is limited to double bond only.
ReplyDeleteI wrote the final structure . I didn't specify colour change. will i get FULL marks?
I did the same mistake in preboards but got half mark! :P
ReplyDelete2NF3 - >> (heat) N2 + 3F2
ReplyDeleteproducts are gases, pressure shoots up, reaction vessel bursts. so, explosive!
the paper was nice although care must have been taken not to repeat such blunders in coming years
ReplyDeletewho had expected a 11th Q. to appear in a 12th AISSCE paper ?
i had solved it but still its not acceptable
and regarding attack of bromine, all the unsaturation will have to be made up by Br2 if Br-water is to be decolourised
so the product is a hexabromo alkane
I am preparing for IIT, so level of questions never bothered me both in Physics and Chemistry. But, not going to get 70 as named that aldehyde as ketone a silly mistake to comit. I was really frustrated by that equilibrium question, solved that one correctly, but was tensed that I didn't get it correctly.
ReplyDeleteare u sure br2 will not reduce triple bond,my frds are saying it will reduce triple bond also
ReplyDeletewhat about dat br2 question? will it reduce triple bond also or not?
ReplyDeleteim writing......
ReplyDeleteeasier than physics!!!!!!!!!!
ReplyDeletehope biology will also be easy
does anyone can tell the correct order for arrangement in the last question of set 1...
ReplyDeletePLEASE...........................
@dnj
ReplyDeletem an iit aspirant!
expecting 95+ in chem!
well m nt much cncerned as iit z approaching!!
hows ur prep??
hey guys)!
ReplyDeletehav u all(iit aspirants) received jee admit cards? :/
i havent found a single person who has received it even though today z d last day..isnt it? ://
it was a very lengthy paper and not standard at all. there was too much asked in even 2 n 3 mark questions. and there was lack of numericals. and few questions were even out of main syllabus and cbse must take into account that students of outskirt schools do not have much facilities n material for study n depend solely on the ncert book. it was really disappointing. and paper should have been set for atleast 4 hours to be able to complete! its really harsh that the board wants to play with students' lives.
ReplyDeleteand also, there were around 3 questions wich were apparently "out of syllabus" for 2012! cbse please take notice....
ReplyDelete@anirudh..Dude paper was of appropriate length finished it in 2.5 hrs and den broke my head on that equilibrium ques.. ques of thermosetting and plastic polymers is also out of syllabus...Even the inter paper in AP was badly made...whats going on wid question paper makers???
ReplyDeletei think physics is more easy than chem...for chem it was a medium paper...also many questions were out of syllabus.....do anybody knows the answer of
ReplyDeleteorganic compound-C9H10O...is it 2-ethyl benzaldehyde....
Yes, the reaction is indeed explosive, but that doesnt define an exothermic compound. An exothermic compound is one whose heat of 'formation' is exothermic, not heat of 'dissociation'
ReplyDeleteHence, the reason is that bcz of very strong bonds formed bw F nd N, the heat of formation is exo.
In case of chlorine lattice energy is less so the overall energy of reaction is endo.
In pent-1-ene 4 yne
ReplyDeletewhen Br2 attacks(considering as bromine water) ,
4 bromo compound will be in major yield.(2 on alkene and 2 on alkyne(trans form))
6 bromo compound will be in minor yield.
Alkyne decolourise bromine water faster than alkene.
but i messed upwith polymer thermoseeting and thermoplastic,but i have a doubt regarding wheteher it was out of syllabus ornot..as this q is given in ncert exercise
ReplyDeleteequilibrium question is out of syllabus and structure of N2o5 is also out of syllabus but the paper is damn easy i hv completed my paper in 2hr and 45 min.
ReplyDeleteexpecting 60 -65 and physics is lengthy but easy.
ReplyDelete@Anirudh...I couldn't keep pace with time either.
ReplyDeleteBut I could have, had I not elaborated the 2 marks answers.There I made mistake in managing time.Sad that I couldn't complete writing up some answers which I knew well.
Still the paper was different from the common pattern,wasn't it?
Well...hoping for the best.
ya...i also got 2-ethyl benzaldehyde.....
ReplyDeletepls anyone confirm this.......
ARE YOU ALL SURE THAT CBSE WOULD GIVE GRACE MARKS FOR THAT "NO" Q? BCOZ NO IMFORMATION HAS COME OUT YET.
ReplyDeleteya i got the same!
ReplyDeleten dis is the answer buddy!
m cnfrmed :) !!!!
i think about 5 marks was out of syllabus.hope that cbse will consider this .che exam was tough for me.dont think tat it's quite easy.
ReplyDeletebio was 2222222...... gud really gud though not all sets. set 1 n 3 were really good .mine was set 3.my fnds who got set2 claimed to be togher than the other 2
ReplyDeleteI think the paper was just fine.Neither too easy nor too difficult; better than physics-as expected. Except the NO2 question- it was from class 11 syllabus. And yeah, for people who had attempted previous years' questions, it sure was cakewalk. If you were not clear about concepts, you're bound to fall flat on your face--in both physics AND chemistry. :)
ReplyDeleteche exam was not at all easy.if cbse do like this ,no one will pass in 12.nd no one will take cbse syllabus for higher secondary.this is a lesson for
ReplyDeletejuniors.
plzz,dont punish us for selecting cbse syllabus
i got no2 qtn but found other qtns out of syllabus.i want 2 knw whether cbse provide mark for it.
ReplyDeleteWas far better than physics i think , hope cbse evaluates physics liberally
ReplyDeleteThe paper was much better than physics.. and i hav come thru a news frm all around that 8 marks are to be given in grace in physicz..??
ReplyDeletefor chemistry i didn't get that NO2 question..!! :/
better than phy... but chemistry is gonna be tough correction i guess... wer they strictly follow their answer keys... so hope for gud marks.
ReplyDeleteu r right.....i think its the ques about peptisation na..........i also think that another numerical was out of syllabus too....a 3m mark ques related eqbm constant...
ReplyDeletegrace mark .....do we get the full 3 mark ......as i hav attempted d ques got some ans but i dont think it is correct
ReplyDeletei got set 2, it was easy 4 me......bt i din go thru the othr 2 sets.......so dunno wethr the othr 2 will b easier or not
ReplyDeletethe numericals had complicated and lengthy sums...it ws lengthy...i hope the teachers do lenient checking..otherwise the overall percentage will be down!!
ReplyDeletefrom where did you get the news that grace will be given to students in physics. please send me the link
ReplyDeleteI didn't say that there will be grace marks. I said that the marking scheme is prepared in such a way as to compensate the problems with the question paper. The students who attempted the questions sincerely will get appropriate marks.
ReplyDeletewell,physics was easy but got confused in few questions.chem. was easy too...bio. contained direct n easy questions.maths was easy but 4 markers were lengthy....hope 2 secure 90+ easily in all subjects.
ReplyDelete4 me it was quite tough....i dnt know whether i will pass.bcoz i didnt know anything.... bt i am sure dat my GOD will help me to score gud marks..
ReplyDeletei trust in U JESUS