JEE Chemistry Club

Abcd

06:35

How was the paper @AvnishKabaj @PolarBear @AdvilSell @YUSUFHASAN @Jasmine ?? All answers correct or not?

Avnish Kabaj

08:32

@Abcd the dunno about correct

But was easy

Abcd

@AvnishKabaj Are you giving AITS Mains on 23rd

Avnish Kabaj

@Abcd nope

Abcd

@AvnishKabaj Y?

Avnish Kabaj

@Abcd Haven't touched jee stuff since a month and a half

Abcd

Saw your paper.

It's easy$^\infty$ !

literally 0 tricky questions.

you all r so lucky!

Avnish Kabaj

08:42

Yeah it's the statements and the time limit which take your marks

@Abcd I mean you could have joined a cbse school

Abcd

No one gave proper advice at the beginning of 11th! And by the time I realised it was too late.

Now I am going to warn all my juniors against opting for this foolish board.

These school teachers pretend to care and love you and even they dont give the right advice. When I attended school in the beginning of 11th and we told our Chem teacher about students who had joined CBSE/ dummy, he was like "Biggest Mistake of their Life".

Avnish Kabaj

Sad

Advil Sell

08:58

@Abcd really easy

YUSUF HASAN

09:16

@Abcd Yeah.. I have solved all of them.. But a few lapses may have occured in the calculation part of the matrix question.. (But anyway,it is step marking).. Otherwise questions were definitely easy

Abcd

@YUSUFHASAN Which matrix question?

The one of system of eq^ns ?

YUSUF HASAN

Yeah.. The values looked very dicey to me.. And I was short on time as well.. But explained the entire procedure.. So probably will lose 1 mark for final answer if it's wrong

Abcd

dude

for that you should have put your answer in the given equation's LHS

to check if you are getting the right RHS

YUSUF HASAN

@Abcd Yeah Ik.. My final answer is of course right... But in b/w.. The value of the determinant and adjoint and stuff... They may have gone a little south.. That's why I say 1 mark

That's to say... If the examiner reads each and every line XD

Abcd

not possible. If final answer is crkt it means steps are correct in that question.

Slightest mistake in adjoint gives wrong answer

@YUSUFHASAN You have one more exam left?

YUSUF HASAN

09:22

@Abcd Arre I solved the 3 equations separately... Then I have put that as the values of x,y and z... But it wasn't coming out exactly the same via matrix method... So got sthg slightly wrong somewhere(a factor was extra IIRC)

@Abcd Yeah... Informatics practices.. 2nd April

Abcd

@YUSUFHASAN :O

Dictatorship XD

YUSUF HASAN

@Abcd Your choice.. You anyway won't be able to "dictate" much if I decided to spam this group with trash messages.. XD

Abcd

@YUSUFHASAN Whats your plan for next 10 days ? Only IP or JEE + IP

YUSUF HASAN

JEE (90-95%).. IP(5%).. Cuz its really easy.. We only have a single book.. Which I have memorized atleast 2-3 times before.. U should really have opted for CBSE! XD

PolarBear

09:56

@Abcd Different regions have different paperssss

Abcd

@PolarBear i guess I checked the all india paper only

PolarBear

It was lengthy for me.

@Abcd It's different in that too.

Abcd

Any hard question for you?

PolarBear

Not hard exactly. But, I solved some questions with different methods and I got some weird answers even though I checked.

It was lengthy for me. Took 4 supplements. 42 + 4(8) pages. I was writing and writing xD

Students in my school couldn't complete papers except for the high scorers.

@YUSUFHASAN Niceee

We have two sections in CS. One section common for all languages and one language section.

I don't know the common one xD Need to study T_T Two big boooks

Hey, for the first time they asked proving formula

In my set it was to prove $\int_{a}^{b}{f(x)} = \int_{a}^{b}{f(a+b-x)}$

Advil Sell

@PolarBear dafq !! 4 supplements !!, I barely completed the answerbook

@PolarBear mine too

PolarBear

10:02

Different sets had different but every set had one

@AdvilSell I was in vroom vroom mode since start, I am happy I could atleast complete xD

Advil Sell

@PolarBear did you suspect any answer

??

PolarBear

I checked while/after writing, so expecting they I didn't do mistake in checking.

@AdvilSell Means?

I did. Some were weird. But I checked it. Sometimes I did wrong, so I cut it and wrote again. Sighhh.

Advil Sell

@PolarBear anything you didn't know , or any part you didn't solved ??

PolarBear

@AdvilSell No, solved and knew everything. Was stuck on transformation proving det at last but finally got it in last minute.

Advil Sell

@PolarBear nice , I didn't remembered the bayes theorm and hence did the question wrong first time , then derived it , it took a lot of time !!

PolarBear

10:08

Sad :P

Advil Sell

@PolarBear :D , I am happy that boards are over !!

almost

YUSUF HASAN

For that integral from 0 to a proof.. I don't suppose we can use a previously proved identity?

PolarBear

@YUSUFHASAN Like?

Oh you had similar proof but instead of a to b you had 0 to a right?

You can't use the a to b one

Some news pages say paper was easy some say it was as tough as physics .-.

@AdvilSell Yeah finally.

YUSUF HASAN

Yeah.. I don't think we can... Lol,I almost did a wowzie there... I first said that we know that this is the identity for (a+b-x).. Now set b=0.... Tada!!(Although I corrected it later there with the actual proof)

PolarBear

Now I have to go to school because my CS teacher thinks I know no CS. I missed last CS pre board xD

Advil Sell

10:20

@YUSUFHASAN lol

PolarBear

@YUSUFHASAN Lol, 2 marks.

No, more marks

Idk

YUSUF HASAN

@PolarBear Yeah.. It was 4 marks.. So 2 for proof and 2 for using it in a question next to it.. The second one I of course did properly

But it had been sooo long since I had proved that identity.. And who even asks that... It isn't needed as such in problem solving

Advil Sell

@YUSUFHASAN my problem was directly asked on the property given to proof

YUSUF HASAN

Yeah same.. I also had to use it in a problem.. That I'm comfortable with.. But I know almost zero proofs in maths.. If I forget sthg.. I'm done for in the JEE! XD

PolarBear

@YUSUFHASAN Many formulae are derivable on spot

Advil Sell

10:25

@YUSUFHASAN sometime proofs are needed in the question of JEE advanced , not much tho

@PolarBear almost all

PolarBear

Whoooosh, I have to now study CS. Sigh. CS tips CS tips

YUSUF HASAN

@PolarBear True.. But those I can derive by sthg I know from prior knowledge.. Like in conics and stuff.. I remember basic formulae and work fro there.. From scratch I almost know nthg to derive

PolarBear

I am bored of board

3

YUSUF HASAN

@PolarBear Dude.. U have more than a week from now.. Why rushing now?

Advil Sell

@PolarBear same :D

PolarBear

10:29

@YUSUFHASAN Otherwise my teacher will ask me to come to school everyday

She's more worried. She even called.

I should be happy right

YUSUF HASAN

@PolarBear Which teacher is so caring in this country? My IP teacher talked to me last time in the month of January.. XD

PolarBear

Hmm, I should be grateful to my teacher. I will thank her nicely.

Goodbye everyone enjoy the holidays

Avnish Kabaj

@PolarBear heh

"holidays"

YUSUF HASAN

@PolarBear Yeah.. You should.. And these are not holidays.. This is a chance for redemption for the JEE.. XD

PolarBear

@AvnishKabaj Me when I hear non JEE people say "I am going to party today."

And me also when they ask me what my plans are. Solving physics. You know. Solving physics.

@YUSUFHASAN Absolutely.

Avnish Kabaj

10:36

@PolarBear ER gawd I should get started

Have to do all of DC pandey level 1

PolarBear

Some are even going to their Native for Holi. Even JEE people.

I don't even know when Holi is.

This makes me feel I am on right track.

Avnish Kabaj

Ok kewl

PolarBear

@AvnishKabaj Whoooo. You have DCP?

Oh wait, which DCP?

Avnish Kabaj

@PolarBear yeah

@PolarBear DC pandey

PolarBear

Problems one or theory one?

Jasmine

10:38

@Abcd missed a 2 mark probability question but the paper was nice

Avnish Kabaj

Which one is the problem one?

PolarBear

@AvnishKabaj Just a single book

Avnish Kabaj

@PolarBear Is it like super good?

Jasmine

Now time for advanced

3

PolarBear

@AvnishKabaj Umm, not really. Moderate. Good for first time solve.

Helps build concepts.

Avnish Kabaj

10:40

@PolarBear ok thanks

PolarBear

Okay good

I also have the 500 problem one. It's good.

Avnish Kabaj

I dont

PolarBear

Very nice.

Advil Sell

@PolarBear the new pattern one ??

PolarBear

@AdvilSell No, the first one is new pattern one.

Idk the 500 one isn't famous I bought it just for fun but it's good

It has only subjectives

Advil Sell

10:43

@PolarBear Ohh...okay :D

PolarBear

But the questions aren't calculative.

Jasmine

What are you all doing today

PolarBear

@Jasmine Partying

google.com/…

Jasmine

Partying by doing what :D

PolarBear

@Jasmine Nice question. I like solving maths to party.

Jasmine

10:44

@PolarBear oh 62

Advil Sell

@PolarBear Probably Praying

Jasmine

@PolarBear I knew it

I will join your party soon in sometime

PolarBear

@AdvilSell I don't pray. I know my fate is my own fate nothing's going to happen xD

@Jasmine lol join in sis

Advil Sell

@PolarBear XD , I was just kidding ( Even I don't pray )

PolarBear

I xD too much

Jasmine

10:46

Ok XD

Avnish Kabaj

तुम सब नरक जाओगे

PolarBear

11:13

वोके, थेँक्यू

Avnish Kabaj

31 mins ago, by PolarBear

@AdvilSell I don't pray. I know my fate is my own fate nothing's going to happen xD

PolarBear

11:39

ई सेड वोके

ई कन्नौ मय बाड़ फेट

Dante

HCl is a stronger acid than HF. Then why does HCl behave as a weak base in HF?

OP tandon physical chemistry page 691

Board exams are done

@AdvilSell chat.stackexchange.com/transcript/message/49538147#49538147

Abcd

12:20

→ 1 message moved to Trash

@Jasmine missed means you didnt see it?

@Dante HF aint able to polarise HCl because HF itself has Hydrogen bonding.

.

PolarBear

in Trash, 48 secs ago, by PolarBear

in Trash, 3 hours ago, by YUSUF HASAN

Anyway.. Wasn't aiming for full(unlike toppers such as @Abcd) XD

Abcd

Yes @ice. Why dont they have separate English and Hindi papers.

Quite irritating to see them together.

Also you must be having situations like "Duh, I started reading the hindi one!"

PolarBear

Yeah, many people have that problem. I just cut the hindi part and questions I am not going to solve. Crooosss crossss

YUSUF HASAN

@Abcd I didn't get Dante's question.. What are you justifying by H-bonding?

PolarBear

@Abcd Happens happens

Abcd

12:24

@YUSUFHASAN He is saying HCl is not strong acid in HF.

And I am saying strength of acid is solvent dependent.

HF is not able to polarise HCl like water. Because HF is self-involved/ preoccupied.

PolarBear

@Dante First, I don't know if this matters but we normally talk of acid when it's aqueous

@Abcd He said it behaves as base?

Abcd

@PolarBear base is a typo. He meant acid.

YUSUF HASAN

I mean.. What I get from his question... Is that why HCl is not as strong as it usually is in standalone aqueous form rather than when it is mixed with HF.. So here of course dissociation of HCl will go down due to (whatever small) dissociation of HF occurs... Common ion effect..

PolarBear

@Abcd He said that HCl is stronger than HF

Abcd

YUSUF HASAN

12:27

@PolarBear No.. I think we meant that HCl becomes weaker in HF

Abcd

Doubt @PolarBear @YUSUFHASAN

PolarBear

@YUSUFHASAN Oh, now I get it

Abcd

@YUSUFHASAN I dont think Common ion effect is right explanation.

Dante

@Abcd I never understood this questions properly, though being a adv 2017 ques it had many solutions online. It was after looking at this ques I lost confidence in thermodynamics X

Abcd

$\ce{H2O(l) (1 bar, \pu{373 K}) -> H2O(g)(1 bar, 373 K)}$

YUSUF HASAN

12:29

@Abcd I mean.. Common ion effect weakens the dissociation of both acids simultaneously,right? Simulataneous equilibrium and all that..?

Abcd

Write $\text{signum}(\Delta G), \text{signum}(\Delta S)$ for this reaction:

1 min ago, by Abcd

$\ce{H2O(l) (1 bar, \pu{373 K}) -> H2O(g)(1 bar, 373 K)}$

@YUSUFHASAN @PolarBear @Dante This easier one as well pls^

@Dante Well, rest of the thermodynamics archive is very easy. Dont get disheartened by 1 or 2 questions.

PolarBear

@Abcd (Okay I don't know that answer but just trying on my getting answer by hook crook method is it (A)?)

YUSUF HASAN

H-bonding is there in HF... But it is quite weak in solution phase.. So i would say that common ion effect is good enough here

Dante

I see

Abcd

@PolarBear Crkt

Dante

12:32

OP says HCl + HF <-> H2Cl+ + F-

PolarBear

(Whoo, lemme think then btw I found out the answer by dimensional analysis)

Dante

So it's not a typo

Abcd

@PolarBear All answers are in bar!! How did you use Dimensional

Dante

@Abcd Calculation for that question is very easy, it's direct XD

PolarBear

@Abcd Not exactly.

Dante

12:33

It's just difficult to understand

Abcd

Answer 2nd question you all.

YUSUF HASAN

@Abcd Where is the 2nd question?

Abcd

@YUSUFHASAN See signum

@PolarBear I tried using : $\Delta G^o = -RT\ln(K_p)$

PolarBear

(deleted because you shouldn't do questions that way lol)

YUSUF HASAN

@Dante Proves my point.. Common ion effect is surely randomising stuff here.. Thats why that equilibrium exists

Abcd

12:35

lol$^\infty$

@YUSUFHASAN I still think its because of low polarity of HF

@YUSUFHASAN Who is stronger Acetic or HF

Dante

Maybe you both could google for a confirmation?

I did but wasn;t satisfied

Abcd

11

Q: Acidity of hydrochloric acid in acetic acid

A question asked to find the $\mathrm pK_\mathrm a$ of $\ce{HCl}$ in acetic acid. The equation of $\ce{HCl}$ disassociating in water is: $$\ce{HCl + CH3COOH \leftrightharpoons CH3COOH2+ + Cl-}$$ I predicted that the $\mathrm pK_\mathrm a$ should be higher as acetic acid is a weaker base than wat...

Thats in acetic

PolarBear

So I opened my book and I have started abcd's question

I don't even remember solving thermo

Abcd

Because of low polarity.

@PolarBear 2nd question first please!!

Thats 1 second question.

7 mins ago, by Abcd

Write $\text{signum}(\Delta G), \text{signum}(\Delta S)$ for this reaction:

7 mins ago, by Abcd

1 min ago, by Abcd

$\ce{H2O(l) (1 bar, \pu{373 K}) -> H2O(g)(1 bar, 373 K)}$

@AdvilSell Are you online

PolarBear

I meant starred* when I was little in class 11

Starred* not started*

(See that's what I did)

(Not really)

@Abcd delta S is Delta H/T

Abcd

12:42

@PolarBear tell answers first

@PolarBear this is so hard!!

PolarBear

You didn't give delta H

@Abcd Not hard

I did it in seconds xD

Abcd

@PolarBear question didnt give

PolarBear

dG is VdP that's the only info reqd

Dante

Is internal energy of solids dependent only on temp just like ideal gases?

Abcd

@PolarBear But we have to derive it too right? Or did you learn this formula?

Dante

12:45

guess not...

YUSUF HASAN

Wait a minute.. Is some info missing?

Abcd

@YUSUFHASAN Which ques?

PolarBear

@Abcd latent heat 40.8 we know

YUSUF HASAN

@Abcd U can derieve it via thermodyanmic sqaure.. dG=VdP-SdT

Abcd

Guys signum just means give the signs.

PolarBear

12:46

I think that's what we will use

YUSUF HASAN

@Abcd The second one.. R u giving us the enthalpy?

PolarBear

@Abcd Oooh didn't know didn't notice either

Abcd

@YUSUFHASAN C my latest message.

PolarBear

So you are talking about system or surrounding or whole?

Abcd

Also sign(0) = 0

@PolarBear Question didnt say anything.

YUSUF HASAN

12:47

Oh.. So entropy change sign is.. Positive? For system?

Let's assume it to be system

Abcd

@YUSUFHASAN Right And $\Delta G$?

PolarBear

@Abcd positive

Abcd

@PolarBear wrong

PolarBear

Someone had linked a question on SE somewhere or I had just read it

Abcd

@YUSUFHASAN wrong

PolarBear

12:49

It's reversible

Abcd

Guys nothing is given in the question.

its IIT 2007 ques

Dante

17 lol

Abcd

No 2007

Dante

no 17

Abcd

@PolarBear 373 K is 100 C not room temp

Dante

12:51

@Abcd Is there anyway I can bookmark this conversation?

I would like to go through it after I finish thermo from NA

Abcd

@Dante See my instructions to bookmark conversation in PSS to nobodyrecog.

PolarBear

We should have bookmarked the conversation on how to bookmark a conversation that would have made bookmarking easier

Abcd

right

oh Ice has also given d instr.

Jun 27 '18 at 3:07, by Anonymous

@Abcd Go to this chat transcript, there is bookmark on right side of the desktop page. Click on it, then click on your 'start message' and then click on your 'end message'. The whole conversation from the start message to the end message will be bookmarked.

@YUSUFHASAN @PolarBear Why is $\Delta G = 0$ ???

PolarBear

It's zero. I said it.

YUSUF HASAN

Oh yes. I didn't see the temperature... And sincd they have given only the forward reaction.. So it will definitely be spontaneous at 100 degree celsius(facepalm, I am stupid)

Abcd

12:53

@YUSUFHASAN For spon. $\Delta G = -ve$

PolarBear

It's zero. Zero. Yay. I'm right. I'm right.

It's equilibrium.

I am acting dumb today.

Abcd

Ice give reason

PolarBear

16 secs ago, by PolarBear

It's equilibrium.

YUSUF HASAN

@PolarBear They have only given forward reaction in the question.. So u can't assume backward reaction here as far as I think

PolarBear

It seems like I have done all thermo questions.

@YUSUFHASAN No. You can.

That's what you have to think.

Dante

12:55

@Abcd Where's chat transcript?

PolarBear

It's an equilibrium we know that.

Abcd

$\ce{P_(white, solid) -> P_(red, solid)}$

Dante

what is chat transcript?

Abcd

@Dante Actually

click Room on LHS

Above your gravatar

PolarBear

@Abcd What to do?

YUSUF HASAN

12:56

@PolarBear Well.. Then delta G is zero.. So?

Abcd

@PolarBear Is it phase transition or not?

YUSUF HASAN

@Abcd I am saying that since it is not given.. I don't know that whether they want us to consider the back reaction and take it as a phase change

Abcd

@YUSUFHASAN ya exactly

@YUSUFHASAN Question 3 or 2?

YUSUF HASAN

@Abcd sign of delta G one

Abcd

@YUSUFHASAN OK I agree with u on that

$\ce{P_{(white, solid)} -> P_{(red, solid)}}$

State if the above reaction is a Phase Transition or Not. @YUSUFHASAN

PolarBear

12:59

@Abcd Allotropes aren't phase transitions but we consider them sometimes

Abcd

@PolarBear Say definite answer. yes or no.

PolarBear

Traditionally, no. But yes. I remember my teacher saying that.

Transcript for