Question

Ethylene glycol reacts with $PC{l_5}$ to give _______.

Answer 1

The organic compound ethylene glycol (IUPAC name: ethane-$1,2$-diol) has the formula ${(C{H_2}OH)_2}$. It is primarily used for two purposes: as a raw material in the production of polyester fibres and in the formulation of antifreeze. It's an odourless, colourless, viscous liquid with a sweet taste.

Complete answer:
The intermediate ethylene oxide is used to make ethylene glycol from ethylene (ethene). According to the chemical equation, ethylene oxide reacts with water to create ethylene glycol:
${C_2}{H_4}O{\text{ }} + {\text{ }}{H_2}O{\text{ }} \to {\text{ }}HO - C{H_2}C{H_2} - OH$
This reaction can be catalysed by acids or bases, and it can take place at neutral pH and at high temperatures. Ethylene glycol yields are highest when the pH is acidic or neutral and there is a significant amount of water present. Ethylene glycol yields of $90\%$ can be achieved under these conditions.
The chemical compound $PCl_5$ stands for phosphorus pentachloride. One of the most common phosphorus chlorides, along with $PC{l_3}$ and $POC{l_3}$. As a chlorinating reagent, $PC{l_5}$ is used. While commercial samples may be yellowish and polluted with hydrogen chloride, it is a colourless, water-sensitive, and moisture-sensitive solid. $PC{l_5}$ reacts with water to release hydrogen chloride and produce phosphorus oxides in its most common reaction.
When ethylene glycol reacts with the excess of phosphorus pentachloride, it gives ethylidene chloride as a main product and phosphorus oxychloride and hydrogen chloride as a by-product.
$C{H_2}OHC{H_2}OH\; + \;2PC{l_5}\; \to \;C{H_2}ClC{H_2}Cl\; + \;2POC{l_3}\; + \;2HCl$
When ethylene glycol reacts with $PC{l_5}$ it gives ethylidene chloride.

Note:
A gem-dihalide is ethylidene chloride. Exceptional A compound with two halogen atoms on the same carbon atom is called a dihalide. The compound ethylidene chloride is isomeric. $1,2$-Dichloroethane is the IUPAC term for ethylidene chloride.