If x atm be the decrease in pressure of A at time t and one mole each
of B and C is being formed, the increase in pressure of B and C will also
be x atm each A(g)      ®      B(g)       +         C(g)
At  t = 0
pi atm
0 atm
0 atm
At time t
(pi–x) atm
x atm
x atm
where, pi is the initial pressure at time t = 0 pt = (pi – x) + x + x = pi + x
x = (pt - pi)
where,  pA  = pi – x = pi – (pt – pi)
 = 2pi – pt
 k = 
i
A
2 303
log p
p
t










(3