Old bottles of ${\mathrm{diethyl}}_{\mathrm{ether}}$ are often contaminated with which dangerous compound?

• A. $\mathrm{Alcohols}$
• B. $\mathrm{Carboxylic\; acids}$
• C. $\mathrm{Peroxides}$
• D. $\mathrm{Aldehydes}$

Answer: (C)

Verified step by step guidance

1. Understand that diethyl ether is an organic solvent commonly used in laboratories and is prone to forming impurities over time when exposed to air and light.
2. Recognize that the main dangerous compound formed in old bottles of diethyl ether is due to its tendency to undergo autoxidation, a reaction with oxygen from the air.
3. Recall that autoxidation of ethers like diethyl ether leads to the formation of organic peroxides, which are highly reactive and potentially explosive.
4. Note that alcohols, carboxylic acids, and aldehydes are not typically formed as contaminants in stored diethyl ether under normal conditions.
5. Conclude that the dangerous contaminants in old diethyl ether are peroxides, and proper testing and disposal procedures should be followed to handle such contaminated solvents safely.