# A question of dispute!

This Question came in my Boards. I solved it, but my friends are getting other answer. So I'm afraid that I lost 4 marks. (Since I know they have studied Chemical Equilibrium more than me and other reason is that his answer was much higher than me)

I'm posting exact wording of question :

Equilibrium constant of Reaction : A2 + B2 \Leftrightarrow 2AB @ 100Â°C is 50

A 1L flask containingg 1 mole of A2 gas is connected to a 2L flask containing 2 Mole of B2 gas. Calculate the no. of mole of AB at 100Â°C at equilibrium.

My friends' answer : 10 Mole

Even a correct answer would suffice.

71
Vivek @ Born this Way ·

1
kunl ·

ok so right answer is 5/3 moles!=1.67 moles!

1
kunl ·

@vivek how on earth did u even FAINTLY think ur friend knew chemical eqb. better?? :P i cn say he does not even know mole concept correctly[3][3].......1 mole of A can produce at max 2 mole of product!!!...........10 moles OMG!!!!!

1
kunl ·

@vivek bhai bata de ye sahi hai ya nahin...my knowledge of chemical eqb. is under JEOPARDY!

1
R2 ·

@ Kunl : Mine came 59 [285]

1
kunl ·

no idea dude how u got that[1][infact if u see the k value is 50......so answer seems too less [3][3]]
but atleast ur answer sounds better than the one by his "friend"!

1
kunl ·

71
Vivek @ Born this Way ·

Board exam mein solution thodi milta hai.. waise agar tum apna solution post karo main sure ho sakta ho..

6
AKHIL ·

10 moles!!!!!!
hahaha

1
kunl ·

@mohit plz read post no. 4!

1
kunl ·

this must open eyes of many students i guess:
19:40

mohit_5990: @kunal ... isse stoiciometry se relate mat karo
mohit_5990: ye formula based ques hai
20:18
mohit_5990: hw can u say that k eqil is 50
mohit_5990: these are not the actual data
20:20
arunavsi.._8640: dont u think mohit that 2 moles of b2 wud have some effect on the rate law expression
20:25
mohit_5990: y r u guys r talking about the no of moles
20:26
mohit_5990: in equil it is all about molarity
20:28
arunavsi.._8640: oh yeah skipped it

i don't have time to say much so just wrote this and pasting it here too[1]
kunl_8072: ok mohit i will give u 1 mole A
20:45
kunl_8072: and 2 mole B
20:45
20:45
kunl_8072: and after jee give me 15*root 2 mole product ok?
20:46
kunl_8072: i hope by that time ur reaction would have aatained equilibrium!.and as u say its molarity that matters let me see those 15*root 2 moles and i would "no,minate u for nobel prize"[1]

1
thumbsdown007 ·

a2 + b2 =2ab

1 2 0 moles intially

1-x 2-x 2x moles at eq.

1-x/3 2-x/3 2x/3 conc at eq.

k = (2x/3)2/ (1-x/3)(2-x/3) =50 => x=0.93

total no. of moles of ab = 1.86

this question came in IIT 1990

6
AKHIL ·

yes the ans i m gettin is 1.86 moles...

thumbsdown is rite...

71
Vivek @ Born this Way ·

k = (2x/3)2/ (1-x/3)(2-x/3) =50 => x=0.93

One Doubt : Is the expression like this :

k = (2x/3)2/ (1-x3)(2-x3) =50 ??

I solved this!! and if not then why?

30
Ashish Kothari ·

I think the intended expression is :

K = \frac{\left( \frac{2x}{3}\right)^2 }{\left(\frac{1-x}{3} \right)\left(\frac{2-x}{3} \right)}=50