Chlorobenzene vs. Chloroethane

Attribute	Chlorobenzene	Chloroethane
Molecular Formula	C6H5Cl	C2H5Cl
Molar Mass	112.56 g/mol	64.51 g/mol
Boiling Point	131.6 °C	12.3 °C
Melting Point	-45.6 °C	-139.8 °C
Density	1.11 g/cm³	0.92 g/cm³
Solubility in Water	0.08 g/100 mL	0.8 g/100 mL
Odor	Sweet, almond-like	Sweet, ether-like

Introduction

Chlorobenzene and chloroethane are both organic compounds that contain chlorine atoms. They have distinct chemical structures and properties, making them useful in various industrial applications. In this article, we will explore and compare the attributes of chlorobenzene and chloroethane, including their physical properties, chemical reactivity, toxicity, and environmental impact.

Physical Properties

Chlorobenzene, also known as monochlorobenzene, is a colorless liquid with a sweet almond-like odor. It has a molecular formula of C6H5Cl and a molecular weight of 112.56 g/mol. Chlorobenzene has a boiling point of 131.6 °C and a melting point of -45.6 °C. It is insoluble in water but soluble in organic solvents such as ethanol and ether.

On the other hand, chloroethane, also called ethyl chloride, is a volatile and flammable liquid with a faint, sweet odor. Its molecular formula is C2H5Cl, and it has a molecular weight of 64.51 g/mol. Chloroethane has a boiling point of 12.3 °C and a melting point of -139.8 °C. It is slightly soluble in water but highly soluble in organic solvents like acetone and benzene.

Chemical Reactivity

Chlorobenzene and chloroethane exhibit different chemical reactivity due to their structural differences. Chlorobenzene is an aromatic compound, meaning it contains a benzene ring. It undergoes substitution reactions, where the chlorine atom can be replaced by other functional groups. For example, chlorobenzene can react with sodium hydroxide to form phenol, a compound widely used in the production of plastics and pharmaceuticals.

On the other hand, chloroethane is an alkyl halide, which means it has a halogen atom attached to an alkyl group. It is more reactive than chlorobenzene and can undergo various substitution and elimination reactions. For instance, chloroethane can react with sodium hydroxide to form ethanol, a widely used solvent and fuel.

Toxicity

Both chlorobenzene and chloroethane possess certain levels of toxicity, although their effects on human health differ. Chlorobenzene is considered to be moderately toxic and can cause harmful effects on the central nervous system, liver, and kidneys. Prolonged exposure to high concentrations of chlorobenzene may lead to symptoms such as headache, dizziness, and nausea. It is also classified as a possible human carcinogen by the International Agency for Research on Cancer (IARC).

Chloroethane, on the other hand, is highly toxic and poses a greater risk to human health. Inhalation or ingestion of chloroethane can cause dizziness, confusion, respiratory distress, and even cardiac arrhythmias. It is also classified as a potential carcinogen by the IARC. Due to its high toxicity, chloroethane is strictly regulated and its use is limited in many countries.

Environmental Impact

Both chlorobenzene and chloroethane can have adverse effects on the environment, particularly when released into water or soil. Chlorobenzene is persistent in the environment and can contaminate groundwater, posing a risk to aquatic organisms. It is also toxic to certain bacteria and can inhibit their growth. However, chlorobenzene is not readily biodegradable and can persist in the environment for a long time.

Chloroethane, on the other hand, has a lower environmental persistence compared to chlorobenzene. It can undergo degradation through various processes, including hydrolysis and biodegradation. However, the release of chloroethane into the environment can still have harmful effects on aquatic life and soil organisms. Therefore, proper handling and disposal of chloroethane are crucial to minimize its environmental impact.

Conclusion

In conclusion, chlorobenzene and chloroethane are two distinct organic compounds with different physical properties, chemical reactivity, toxicity, and environmental impact. Chlorobenzene is a colorless liquid with a sweet odor, while chloroethane is a volatile and flammable liquid with a faint, sweet odor. Chlorobenzene is an aromatic compound and undergoes substitution reactions, while chloroethane is an alkyl halide and exhibits various substitution and elimination reactions. Both compounds have toxicity concerns, with chloroethane being more toxic than chlorobenzene. Additionally, both compounds can have adverse effects on the environment, with chlorobenzene being more persistent. Understanding these attributes is essential for the safe handling and use of these chemicals in various industries.