a)
A  + B   ßà C Â
+Â Â D
2Â Â Â Â Â
2Â Â Â Â Â Â Â Â Â Â
0Â Â Â Â Â 0
2-x   Â
2-x       Â
x      x
Kc = x^2 / (2-x)^2
5.2 = (x/(2-x))^2
x/(2-x) = sqrt (5.2)
x/(2-x) = 2.28
x = 4.56 – 2.28*x
3.28*x = 4.56
x = 1.39 M
[A] = 2-x = 2 – 1.39 = 0.61 M
Answer: 0.61 M
b)
A  + B   ßà C Â
+Â Â D
1Â Â Â Â Â
2Â Â Â Â Â Â Â Â Â Â
0Â Â Â Â Â 0
1-x   Â
2-x       Â
x      x
Kc = x^2 / (2-x)(1-x)
5.2 = x^2 / (2-3x+x^2)
5.2*x^2 -15.6*x +10.4 = x^2
4.2*x^2 – 15.6*x + 10.4 = 0
solving above quadratic equation we get,
x = 2.84 and x=0.87
x can’t be 2.84 as it will make concentration of A and B
negative
so,
x = 0.87 M
[D] = 0.87 M
Answer: 0.87 M
