Here’s what I can find that gives a better answer. Above 100ppm, you’ll rapidly start feeling dizzy. But chloroform is also highly volatile, so you would need to have a rag soaked in chloroform just before attacking someone, rather than lying in wait for a few minutes to a few hours. Plus, if you get that concentration too high, you can accidentally kill someone.
So if you’d been hiding in someone’s car for 10 minutes, that rag might have lost enough efficacy that it would take a few minutes. Alternatively, if the person in the backseat doused the rag just before attacking the driver, it might be nearly instant.
Here’s what I can find that gives a better answer. Above 100ppm, you’ll rapidly start feeling dizzy. But chloroform is also highly volatile, so you would need to have a rag soaked in chloroform just before attacking someone, rather than lying in wait for a few minutes to a few hours. Plus, if you get that concentration too high, you can accidentally kill someone.
So if you’d been hiding in someone’s car for 10 minutes, that rag might have lost enough efficacy that it would take a few minutes. Alternatively, if the person in the backseat doused the rag just before attacking the driver, it might be nearly instant.