Explanation:
Given:
- Initial concentration (A₀) = 0.0310 M
- Final concentration (A) = 0.00725 M
- Rate constant (k) = 3.00 × 10^-3 s^-1
- Reaction is first-order, so the equation is: ln(A/A₀) = -kt
Rearrange the equation to solve for time (t):
t = -ln(A/A₀) / k
Plug in the values:
t = -ln(0.00725 / 0.0310) / (3.00 × 10^-3 s^-1)
= -ln(0.233) / (3.00 × 10^-3 s^-1)
= 531.5 s
Therefore, it will take approximately 531.5 seconds for the concentration of CH₃NC to decrease from 0.0310 M to 0.00725 M.
