In an experiment, as temperature increased from 20°C to 80°C, reaction rate doubled every 10°C. If the initial rate is 4 units/s at 20°C, what is the rate at 50°C?
✓ Correct Answer: Option B
Rate doubles 3 times (20→30→40→50): 4 → 8 → 16 → 32 units/s.