Question

At 500k the half life period of a gaseous reaction at an intial pressure of 80kpa is 350s when the pressure is 40kpa the half life period is 175s the order of the reaction is

Answer 1

• The order of the reaction is zero.

Given-

• Temperature = 500 K (constant)
• Initial pressure (P₀) = 80 k Pascal
• Half life period at initial pressure = 350 seconds
• Pressure changes to = 40 k Pascal
• Half life period change to = 175 seconds

Here when Pressure become, half life will also becomes half (from the given data)

Which means pressure and half life are directly proportional.

Now, We know that for zero order reaction-

t 1/2 = A₀ / 2K = P₀ / 2K

This clearly shows that half life is directly proportional in the case of zero order reactions.

So order of the reaction is zero.

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