Question

What happens when a mixture of ethene and hydrogen is passed over nickel at $150°\mathrm{C}$.

Answer 1

In an organic reaction, the reagent reacts with a reactant molecule to produce an intermediate which is converted into final products.

The organic compounds containing Carbon $\left(\mathrm{C}\right)$ atoms having double bonds between two Carbon atoms are called unsaturated hydrocarbons.

Ethene $\left({\mathrm{C}}_2{\mathrm{H}}_4\right)$ contain double bonds between the carbon atoms so it is an unsaturated hydrocarbon.

A chemical reaction in which two or more reactants react together to form a single larger product is called an addition reaction.

In the reaction of an alkene with a hydrogen molecule in the presence of a metal catalyst, a hydrogen molecule is added to the double to form the saturated product.

So this addition reaction is known as a hydrogenation reaction.

The reaction of Ethene $\left({\mathrm{C}}_2{\mathrm{H}}_4\right)$ with Hydrogen $\left({\mathrm{H}}_2\right)$ in the presence of Nickel $\left(\mathrm{Ni}\right)$ at $150°\mathrm{C}$.can be written as:

$$\begin{gathered} {\mathrm{CH}}_2={\mathrm{CH}}_2+\mathrm{H}-\mathrm{H}\stackrel{\mathrm{Ni}/150°\mathrm{C}}{\to }{\mathrm{CH}}_3-{\mathrm{CH}}_3 \\ \left(\mathrm{ethene}\right)\left(\mathrm{hydrogen}\right)\left(\mathrm{ethane}\right) \end{gathered}$$