Mechanism of a hypothetical reaction $\require{mhchem}\ce{X2 + Y2 -> 2XY}$, is given below :
(i) $\ce{X2 -> X + X}$ (fast)
(ii) $\ce{X + Y2 \rightleftarrows XY + Y}$ (slow)
(iii) $\ce{X + Y -> XY}$ (fast)
The overall order of the reaction will be
(a) 2
(b) 0
(c) 1.5
(d) 1
(i) $\ce{X2 -> X + X}$ (fast)
(ii) $\ce{X + Y2 \rightleftarrows XY + Y}$ (slow)
(iii) $\ce{X + Y -> XY}$ (fast)
The overall order of the reaction will be
(a) 2
(b) 0
(c) 1.5
(d) 1