Question

For the reaction, Br2(g) = 2Br(g) the equilibrium constant, Kis 1.10 X 10 at 1280°C. Determine the initial and equilibrium concentrations of Brif the initial and equilibrium concentrations of Br are 5.80 x 10-3 Mand 5.10 x 10 3 M, respectively. [Br]:- [Br] - M

Answer 1

• ② the reaction ginen in the Question is shown below Brg (g) = 2Br (9) Equile' býum constant (Kc) = 1•10 x 10-3 - Temperature = 1280°c Intial concentration of Br = ? final concer Equilibrium concentration of Br =? Inital concentration of Br = 5.80x10-3M Equilibrium concentration - Silox100M

let ci is the initial concentration of Br. Bro (g) ? 2 Br (g) At t=0, 5. do x10 m CiM. change in concentration -x + 2x. At equilibrium (5080x10)M (C° +2x) M. Here, x is the degree of dissociation But, it is given at equilibrium concentration - of Brg 5.10 x 10!3M - ☺ Therefore, from equation 0 2 2 (5.80x10² - x) M= 5.108 10-3 h X = (5.80 - 5010) X10-3 x= 0.7 x 10-3

The expression for equilibrium constant is shown below! Ke = [Br] ² - ③ Substitute the corresponding values in eq.& Polo x103 = [ C° + (Q X 0.7x10-3) ] - Soto X 70-3 5- 61 X10 ° M = (c+ | L X 5-3) G® +104x10 3 = 5-61X10-6 Ci +104x1029 = 2.37 x 10-3 co = 2• 37 X10 3 -1.4810-3 0.97x10-3 M.

Therefore, the initial concentration of By is 0.978103 Hence, final concentration of Br= citga = 0.974103 + 2X0078103. = 0.97X10 + 104 x 10-3 = 2: 37 x 10-3 M.