Question

If a substance conducts electricity at room temperature but does not conduct electricity when dissolved in water, what can be concluded about its purity?

A) It is likely pure.
B) It is likely impure.
C) Purity cannot be determined from this information.
D) It depends on its melting point.

Answer 1

Fermentation is carried out at 30°C because it is the optimal temperature for yeast activity, allowing enzymes to convert sugars to ethanol and CO₂; at 80°C, the yeast would be killed.

Step-by-step explanation:

The correct answer for why the fermentation reaction is carried out at 30°C rather than at 80°C is C) 30°C is optimal for the yeast's activity, while 80°C would kill the yeast. Yeast cells, such as Saccharomyces cerevisiae, are the microorganisms responsible for the fermentation process, in which sugars are converted to ethanol (C₂H₅OH) and carbon dioxide (CO₂). At 30°C, yeast enzymes like pyruvate decarboxylase and alcohol dehydrogenase function efficiently, producing ethanol and additional beneficial byproducts. However, at temperatures as high as 80°C, the yeast cells would be denatured and killed, stopping the fermentation process altogether and yielding no ethanol. Ethanol fermentation is widely used in the production of alcoholic beverages, making bread rise, and in biofuel production.