What is the purpose of using ultraviolet light in organic chemistry labs?

What is the purpose of using ultraviolet light in organic chemistry labs?

• A. To evaporate solvents
• B. To visualize compounds on a TLC plate
• C. To initiate chemical reactions
• D. To measure the boiling points of compounds

Answer: (B)

Using ultraviolet light in organic chemistry laboratories is primarily employed to visualize compounds on a thin-layer chromatography (TLC) plate. Many organic compounds do not have an intrinsic color or visible marker, making it challenging to identify their presence on a TLC plate after development. When UV light is applied, certain compounds can absorb this light and either fluoresce or appear as dark spots against a fluorescent background. This visual representation allows chemists to determine the position of the compounds, assess the effectiveness of a separation, and gather information about the number of components in a mixture. The other options do not align with the primary use of ultraviolet light in this context, as solvents are typically evaporated using heat rather than UV light, UV light does not initiate most chemical reactions in organic chemistry labs, and boiling points are measured using other techniques such as distillation or using a boiling point apparatus, rather than UV light exposure.

Using ultraviolet light in organic chemistry laboratories is primarily employed to visualize compounds on a thin-layer chromatography (TLC) plate. Many organic compounds do not have an intrinsic color or visible marker, making it challenging to identify their presence on a TLC plate after development.

When UV light is applied, certain compounds can absorb this light and either fluoresce or appear as dark spots against a fluorescent background. This visual representation allows chemists to determine the position of the compounds, assess the effectiveness of a separation, and gather information about the number of components in a mixture.

The other options do not align with the primary use of ultraviolet light in this context, as solvents are typically evaporated using heat rather than UV light, UV light does not initiate most chemical reactions in organic chemistry labs, and boiling points are measured using other techniques such as distillation or using a boiling point apparatus, rather than UV light exposure.