Q74 / 180 · NEET 2016 (Phase 2) · Chemistry

The decomposition of phosphine PH3 on tungsten at low pressure is a first-order reaction. It is because the

  • Correct answer
    A
    rate is proportional to the surface coverage.
  • B
    rate is inversely proportional to the surface coverage.
  • C
    rate is independent of the surface coverage.
  • D
    rate of decomposition is very slow.

Solution

The rate is proportional to the surface coverage.

When pressure is so low that αp<<1,

Rate=krαp1+αp≈krαp.

Hence, the correct answer is option: 'A'.

Relevant Questions