For the process
H₂O(l) $$\to$$ H₂O(g)
at T = 100^oC and 1 atmosphere pressure, the correct choice is

Hydrogen peroxide in its reaction with KIO₄ and NH₂OH respectively, is acting as a

For the elementary reaction M $$\to$$ N, the rate of disappearance of M increases by a factor of 8 upon doubling the concentration of M. The order of the reaction with respect to M is