Which time interval has the fastest reaction

• At $t=0$ min, Volume = $0 \text{ mL}$
• At $t=1$ min, Volume = $9 \text{ mL}$
• At $t=2$ min, Volume = $16 \text{ mL}$
• At $t=3$ min, Volume = $21 \text{ mL}$
• At $t=4$ min, Volume = $24 \text{ mL}$
• At $t=5$ min, Volume = $26 \text{ mL}$

• First minute (0-1 min): $$\text{Rate} = \frac{\text{Volume at } 1 \text{ min} - \text{Volume at } 0 \text{ min}}{1 \text{ min}} = \frac{9 \text{ mL} - 0 \text{ mL}}{1 \text{ min}} = 9 \text{ mL/min}$$
• Second minute (1-2 min): $$\text{Rate} = \frac{\text{Volume at } 2 \text{ min} - \text{Volume at } 1 \text{ min}}{1 \text{ min}} = \frac{16 \text{ mL} - 9 \text{ mL}}{1 \text{ min}} = 7 \text{ mL/min}$$
• Third minute (2-3 min): $$\text{Rate} = \frac{\text{Volume at } 3 \text{ min} - \text{Volume at } 2 \text{ min}}{1 \text{ min}} = \frac{21 \text{ mL} - 16 \text{ mL}}{1 \text{ min}} = 5 \text{ mL/min}$$
• Fourth minute (3-4 min): $$\text{Rate} = \frac{\text{Volume at } 4 \text{ min} - \text{Volume at } 3 \text{ min}}{1 \text{ min}} = \frac{24 \text{ mL} - 21 \text{ mL}}{1 \text{ min}} = 3 \text{ mL/min}$$
• Fifth minute (4-5 min): $$\text{Rate} = \frac{\text{Volume at } 5 \text{ min} - \text{Volume at } 4 \text{ min}}{1 \text{ min}} = \frac{26 \text{ mL} - 24 \text{ mL}}{1 \text{ min}} = 2 \text{ mL/min}$$

The rates are:

• First minute: $9 \text{ mL/min}$
• Second minute: $7 \text{ mL/min}$
• Third minute: $5 \text{ mL/min}$
• Fourth minute: $3 \text{ mL/min}$
• Fifth minute: $2 \text{ mL/min}$

The fastest reaction rate is $9 \text{ mL/min}$, which occurs in the first minute.

The time interval with the fastest reaction is the $\text{first minute}$.