Answer
A
Explanation:
CH3NC --> CH3CN
k = 0.46 s–1
In first order reactions, the reaction rate is directly proportional to the reactant concentration and the units of first order rate constants are 1/sec.
So the reaction is a first order reaction.
t = 0.20 min = 12 s ( Converting to seconds multiply the time value by 60)
initial concentration [A]o = 0.10 M
Final Concentration [A] = ?
Formular relating these parameters is given as;
Making [A] subject of interest, we have';
ln[A] = ln[A]o − kt
In[A] = In(0.10) - (0.46*12)
In[A] = -7.8226
[A] = e^(-7.8226)
[A] = 0.000401
[A] = 4 * 10^-4M