The reaction of hydrogen and iodine monochloride is given as :                                     ${\text{H}}_{\text{2}}\left(\text{g}\right)\text{\hspace{0.17em}+\hspace{0.17em}2ICl}\left(\text{g}\right)\to \text{\hspace{0.17em}2HCl}\left(\text{g}\right){\text{\hspace{0.17em}+\hspace{0.17em}I}}_{\text{2}}\left(\text{g}\right)$  The reaction is of first order with respect to ${\text{H}}_{\text{2}}\left(\text{g}\right)\text{\hspace{0.17em}and\hspace{0.17em}ICl}\left(\text{g}\right)$. Following mechanisms were proposed.

Mechanism A :

${\text{H}}_{\text{2}}\left(\text{g}\right)\text{\hspace{0.17em}+\hspace{0.17em}2ICl}\left(\text{g}\right)\to \text{\hspace{0.17em}2HCl}\left(\text{g}\right){\text{\hspace{0.17em}+\hspace{0.17em}I}}_{\text{2}}\left(\text{g}\right)$

Mechanism B :

${\text{H}}_{\text{2}}\left(\text{g}\right)\text{\hspace{0.17em}+\hspace{0.17em}ICl}\left(\text{g}\right)\to \text{\hspace{0.17em}HI}\left(\text{g}\right)\text{;\hspace{0.17em}slow}$

$\text{HI}\left(\text{g}\right)\text{\hspace{0.17em}+\hspace{0.17em}ICl}\left(\text{g}\right)\to \text{\hspace{0.17em}HCl}\left(\text{g}\right){\text{\hspace{0.17em}+\hspace{0.17em}I}}_{\text{2}}\left(\text{g}\right)\text{:\hspace{0.17em}fast}$

Which of the above mechanism(s) can be consistent with the given information about the

reaction?