NEWLY ADDED QUESTIONS unsolved questions are underlined.
1.for what value of k the system of linear equations x+2y+x=1;x+3y+4z=k;x+5y+10z=k2 has solution?find the solution in each case. [roorkee 97] SOLVED
2.true/false(plz give reasoning as well):
i.graphite is a better lubricant on moon than on earthans:F SOLVED
ii.CCl4 is inflammable. ans:F SOLVED
3.complete the reaction: SOLVED
Zn+dil HNO3→
Will add more later.
132) i- Yeah arka, Yahaan bhi True supported hai-
http://books.google.co.in/books?id=0-cDAAAAMBAJ&pg=PA818&lpg=PA818&dq=graphite+is+a+better+lubricant+on+moon&source=bl&ots=P_r7JasXWo&sig=sCSnmaONTVN9HAM_04v3yIBcL4c&hl=en&ei=Vay0S57lD5GtrAejqvxB&sa=X&oi=book_result&ct=result&resnum=6&ved=0CCAQ6AEwBQ#v=onepage&q=graphite%20is%20a%20better%20lubricant%20on%20moon&f=false
398. a), b), d) if the question is asking for the factors upon which oxidation potential depends.
a), d) if the question is asking for those factors which support it.
110. jee 09:multi correct SOLVED
the compounds formed upon combustion of Na in excess air are:
a)Na2O2 b)Na2O c)NaO2 d)NaOH
ans given a,b,'d'.shudnt it b only a,b?
11.
SOLVED
1q 5.)proceeding as avinav did,
exactly what pritish stated.
that's what confused me yesterday.
got the answer now[1]
ques 2(i),7,10,11 still unsolved.
111. none.
am getting RHL=0 and LHL=sin 1,so limit does not exist.
please verify.
110.>
NaOH is obtained when it reacts with moist air
while other 2 obtained with dry air
1@ Arka
u saw the solutions from any institution na....dont believe in them
IIT themselves released the solutions to IITJEE 2009....get it at the JEE 2010 site previous papers link
dil kush ho jayega....................[4]
ans is A,B
13100% on agreement with rick.
Get the 07,08,09 pprs & sol.n frm the JEE websites itself...most reliable & accurate :)
11) Yes, should be d).
1r u sure of 2(i)
in my solutions it is given true
reason is that the gravity on moon is less ...so friction will be less n graphite will be more slippery
confirmed form my sirs....
15.) USING KINETIC THEORY OF GASES
V=√3RTM
MOW MULTIPLY h/λ ON BOTH SIDES
SO
λ IS α √MT
SUSTITTUE THE VALUS TO GET (A) AS THE ANS=1.633
1yeah me too was confused.
graphite q was taken from fiitjee past year iit questions.
Na ques was taken from the solution booklet of jee 09 by an institute 'prerena classes'got from school on farewell that 2 for free[3].
anyway thanks everyone for the verification.was really doubtful regarding these.
1SOLVED
please give reason or show working of ur method.
12. multi correct:
13.When mercuric iodide id added to aq KI solution,then:
a)freezing pt is raised
b)freezing pt is lowered
c)freezing pt doesnt change
d)boiling pt doesnt change
14.What is the gas evolved when PbO2 reacts with conc HNO3?
1freezing point is raised....dis is due to formation [HgI4] - complex which results in -ve vant hoff factor.....
too lazy to show u the calculations........u can do it urself
2112) hint:: every perfect odd square is of form 8k+1
after tat use some property of deters...
i think u shud get it then.
1thanks 4 d verification,govind.it was a single option correct q from fiitjee and the ans was given as O2 when both O2 and NO2 were given.
raja 12 is multi correct,ans are A,C.
madhu ans for 7 is given on #19 of this thread.its a bizarre ans,am gettin nowhere near it[3]from ADG,hopefully not wrong ans
1A few final doubts.plz reply with reasoning
1.A solution of Na in liquid NH3 at -33°C conducts electricity.On cooling the conductivity of this solution _______.
ans:decreases
1thanks a lot avik and eragon[1].
few more:plz tell the method to proceed,just not the ans
5.ratio of de broglie wavelengths of molecules of H2 and He at 27 and 127°C respectively is:
a)1.633 b)0.612 c)1.265 d)0.79 ans:A
6.
SOLVED
shouldnt answer be d?
answers to T/F were both false saket.
212)
i)true- as there will be lesser friction on moon......so function of lubricants will be easier.
ii)false......reason is that actually ccl4 is used in fire extinguishers.[11]
39arka if A is a singular matrix I think it has no solution...I don't remember. Will consult theory and tell you.
39And in the metre bridge question, the null point which is closest to the midpoint of the scale will give most accurate reading. This is given in any lab manual, they show you how by error calculations that X = x/2 is the best spot and anything near it will give accurate reading. So the ans should be B.
1thanks pritish.
you r right regarding metre bridge question.
saket,will verify ur answers 2moro.
regarding q 1,if Δ=0,there can still be a case of infinite solutions,cant it be pritish.
havent solved any of that type so need solution of this sum.
133) came last yr i think in match the columns, dunno exactly.
Anyways, this is an exceptional case when Zn reacts with dil. HNO3,
* 2HNO3 ----> H2O + N2O + 4O (gives N2O instead of NO)
* Zn + O ----> ZnO
* ZnO + 2HNO3 -----> Zn(NO3)2 + H2O
Now Multiply/Add/Cancel out....u'll get the reaction.
211st
here since D=0
so for having infinite soln u will hav D1= D2= D3=0
D1 D2 D3 denote the standard notation for determinants
