The decomposition of phosphine P H 3 on tungsten at low pressure is a first-order reaction. It is because the

The decomposition of phosphine

(P H_{3})

on tungsten at low pressure is a first-order reaction. It is because the

rate is proportional to the surface coverage.
rate is inversely proportional to the surface coverage.
rate is independent of the surface coverage.
rate of decomposition is very slow.

Solution

The rate is proportional to the surface coverage.
When pressure is so low that

αp < < 1

,

Rate = \frac{k_{r} αp}{1 + αp} \approx k_{r} αp

.

Asked in: NEET 2016 (Phase 2)

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