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The isomerization reaction CH3NC (g) <---> CH3CN (g) obeys the first order rate law. At 500K,...

The isomerization reaction CH3NC (g) <---> CH3CN (g) obeys the first order rate law. At 500K, the concentration of CH3NC is 85% of its original value after 247s. What is the rate constant for this decomposition at 500K? At what time will the concentration of CH3NC be 25℅ of its original value?

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Answer #1

for the first order reaction we know that

where Ca = Concentration at any time t

Cao = intial concentration

K = rate constant

t = time

according to the problem Ca = 0.85 Cao at t=247s

therefore putting the values we get,

therefore value of K = sec-1

for the next part..

given that Ca = 0.25 Cao

therefore again using the formula

we get

therefore t= 2110.037 sec

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