3what is Kx???
N2 + 3 H2 → (equilibrium) 2NH3
is a gaseous phase equilibrium reaction taking place in a 5-litre flask at 400 K. For this choose the correct alternative :
A) Kc = Kx B) Kc = 25 Kx
C) Kx = 25 Kc D) Kc = 5 Kx
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8 Answers
1Kx is the equilibrium constant w.r.t the mole fractions of each substance at equilibrium.
Kp = Kc(RT)Δn
Kp = Kx pΔn
1N2 + 3H2 = 2NH3
a b 0
a-x b-3x 2x
KC = ( 2x/500)2
____________
(a-x/500)*(b-X/500)3
TOTAL NO OF MOLES AT EQ.= (a+b-2x)
TOTAL PRESSURE AT EQ= (a+b-2x) R 400
__________
500
PARTIALL PRESSURE OF N2=(a+b-2x)*R*400*(a-x)
____________________
500*(a+b-2x)
SIMILARLY, FIND PARTIAL PRESSURES OF OTHERS AND FIND KP. IT WILL BE FREE OF (a+b-2x).SO CAN BE COMPARED TO KC
1357Kx is not a fixed quantity. It depends on the total pressure of the system.
So for the reaction, we can't tell unless the total pressure is given
1sir but wont the pressure at equilibrium depend on the state of eq,(i mean a+b-2x) which will be constant for a particular value of equilibrium constant .the pressure is found out using the other conditions at eq
1dont need to know that. kp /kx is coming out to be a fixed quantity