Synthesis of Ethanol

In the laboratory synthesis of ethanol, which carbohydrate serves as the substrate for fermentation?

Glucose (C6H12O6)

What biological agent is used to produce the enzymes necessary for the fermentation of glucose into ethanol?

Yeast.

What is the purpose of adding a nutrient solution to the glucose and yeast mixture during synthesis?

It supports yeast growth.

Which gas is evolved during the fermentation process as a byproduct of ethanol production?

Carbon dioxide (CO2).

What reagent is used to detect the presence of $CO_2$ by turning milky?

Lime water.

Provide the balanced chemical equation for the fermentation of glucose.

C6H12O6 > 2C2H5OH + 2CO2

How long was the fermentation process allowed to proceed in the experimental procedure?

One week.

Which technique is employed to purify ethanol from the fermentation mixture?

Distillation.

Describe the physical color of pure synthesized ethanol.

Colorless.

What is the characteristic odor of ethanol?

A mild, sweet alcoholic smell.

What is the approximate specific gravity of ethanol?

0.79.

How does the specific gravity of ethanol compare to that of water?

It is less than water.

What is the boiling point of ethanol?

Approximately 78 C

What is the result of the combustion test for ethanol?

It burns with a clean blue flame.

What reagents compose the Lucas test reagent?

Hydrochloric acid (HCl) and Zinc chloride (ZnCl2).

What is the result of the Lucas test when performed on ethanol at room temperature?

No turbidity is observed.

What structural classification of ethanol is confirmed by a negative Lucas test result at room temperature?

Primary alcohol.

Which two chemicals are reacted with ethanol to perform the esterification test?

Acetic acid (CH3COOH) and sulfuric acid (H2SO4).

What is the name of the ester formed during the esterification of ethanol with acetic acid?

Ethyl acetate (CH3COOC2H5).

Provide the chemical equation for the esterification of ethanol.

C2H5OH + CH3COOH > CH3COOC2H5 + H2O

What sensory evidence indicates a successful esterification reaction?

The formation of a fruity or sweet odor.

Name two medical uses for ethanol mentioned in the material.

Antiseptic and disinfectant.

How is ethanol utilized in the pharmaceutical industry besides as an active ingredient?

As a solvent.

What is the term for ethanol when it is used as a renewable power source?

Bioethanol (fuel).

What is the bactericidal concentration range for ethyl alcohol?

60% to 90%.

Which specific concentration of ethanol is considered most effective for bactericidal use?

70%.

What are the two most important modern sources of ethanol?

Fermentation of sugars and petrochemical synthesis.

Through what chemical process is ethanol synthesized from petroleum products?

Hydration of ethylene.

What are the two primary mechanisms of action by which ethanol kills cells?

Denaturing proteins and disrupting cell membranes.

How does increasing the carbon chain length of an aliphatic alcohol affect its antimicrobial activity?

It increases antimicrobial activity up to a certain limit.

How does branching in the structure of an alcohol affect its bactericidal effectiveness?

It reduces effectiveness.

Generally, which is more effective as a bactericide: primary alcohols or tertiary alcohols?

Primary alcohols.

Which alternative alcohol possesses antiseptic properties equal to those of ethyl alcohol?

Isopropyl alcohol (isopropanol).

The process of using yeast to convert glucose into alcohol and gas is called _____.

Fermentation.

In the Lucas test, the appearance of _____ would indicate the presence of a secondary or tertiary alcohol.

Turbidity (cloudiness).

Term: Ethyl acetate

Definition: An ester produced from ethanol and acetic acid, characterized by a fruity smell.

In the experimental procedure, how is the $CO_2$ confirmed after leaving the fermentation flask?

It is passed into lime water to see if it turns milky.

What role does sulfuric acid play in the esterification identification test?

It acts as a catalyst for the reaction between ethanol and acetic acid.

Identify the substance: Colorless liquid, $BP \approx 78 ^\circ C$, burns blue, primary alcohol.

Ethanol (Ethyl alcohol).

Why is ethanol preferred as a laboratory reagent in organic chemistry?

It serves as a versatile solvent and starting material for synthesis.

What industrial feedstock for fermentation includes sugarcane, corn, and fruits?

Sugars.

Ethanol kills bacteria primarily by denaturing their _____.

Proteins.

What physical property describes ethanol's weight relative to water, measured at approximately 0.79?

Specific gravity.

Which identification test requires heating the mixture to observe a change in odor?

Esterification.

The reaction $C_2H_5OH + CH_3COOH \rightarrow CH_3COOC_2H_5 + H_2O$ is an example of what type of reaction?

Esterification.

What is the expected result of a combustion test for a pure sample of ethanol?

A clean blue flame.

Is ethanol more or less effective as a disinfectant when branched?

Less effective.

Which reagent is used as a solvent for the glucose during the initial step of the synthesis?

Water.

What is the end goal of the distillation step in the synthesis of ethanol?

To collect and purify the ethanol produced during fermentation.

The evolution of which gas serves as the primary indicator that fermentation is occurring?

Carbon dioxide (CO2)