Passage II
The Indian beech tree (Millettia pinnata) produces oil-rich seeds. The oil is inedible; however, it can be converted to biodiesel fuel in a chemical reaction with methanol (a solvent) and a catalyst. Scientists studied the production of biodiesel fuel from M. pinnata oil.
Experiment
In each trial, the following steps were performed:
1. Twenty mL of M. pinnata oil was mixed with 80 mL of methanol in a flask to form a solution.
2. A particular mass of a catalyst一either sodium hydroxide (NaOH) or potassium hydroxide (KOH)—was dissolved in the flask.
3. The flask was fitted with a temperature probe, sealed, placed in a microwave oven, and then microwaved until the contents reached 60°C.
4. The flask was maintained at 60°C in the microwave for a particular amount of time (the microwave time).
5. The flask was immersed in an ice water bath.
6. The amount of biodiesel fuel produced was measured and the percentage of the M. pinnata oil that had been converted to biodiesel fuel was calculated.
For any given combination of conditions (identity of catalyst concentration of catalyst, and microwave time), 4 trials were conducted. The table shows, for each set of trials, the experimental conditions and the average percent of the oil that was converted to biodiesel fuel.
8. Which step was most likely performed to stop the reaction that was occurring in the flask ?
Your Answer is
Correct Answer is H
Explanation
Reduce the temperature of the flask, low temperature can prevent the reaction from happening.