Question

for the reaction
2HCL------->h2+cl2
the KC is 1.0*10-6. if the equilibrium concentration of H2 and cl2 are 1.2*10-2 Mand 1.2*10-4M respectively the concentration of HCL is
answer=1.2*10-2
how???...plz fasssstttt​

Answer 1

Answer:

Let initial number of moles of HCl be N in the container of volume V litres.  Let there be X moles of H2 and X moles of Cl2 at the equilibrium.

      2 H Cl (g)  <===> H2 (g)   +   Cl2 (g)

     N-2X moles       X moles    X moles  

Equilibrium constant Kc = [ H2] [ Cl2] / [HCl ]²

     Kc = (X/V)² ÷ {(N-2X) / V}² = 4 * 10⁻³⁴  

          = X² / (N-2X)²  = 4 * 10⁻³⁴

This means that  X/(N-2X ) = 2 * 10⁻¹⁷

         N-2X = 5 * 10¹⁶ X

         X ≈ 2 * 10⁻¹⁷  N

So X is very very small compared to N.. Equilibrium shifts towards the left.

Explanation: