Question

Methane (from natural gas) is mixed with steam, and compressed at $30{\text{ atm}}$ passed over Nickel at about ${800^ \circ }C$ to form what?

Answer 1

Methane $C{H_4}$ is the smallest member of alkane hydrocarbon family which reacts with steam (the gaseous form of water) at drastic conditions of high temperature and pressure over the Nickel surface being used as a catalyst.

Complete answer:
Hydrocarbons with lower molecular masses tend to react with water in its different forms. At the drastic conditions of high temperature ${800^ \circ }C$ and high pressure $30{\text{ atm}}$ methane gas obtained from natural resources like feedstock and steam react with each other to give carbon monoxide and hydrogen gas.
The hydrogen is produced in its diatomic form and is sometimes referred to as ‘grey hydrogen’.
The combination of carbon monoxide and hydrogen gas is known as syngas. This reaction between steam and methane $C{H_4}$ is known as steam reforming or steam methane reforming reaction. It is mainly carried out to produce large amounts of hydrogen gas.
The Nickel metal surface allows the gaseous reactants to get adsorbed and provides a larger area for the reaction to take place efficiently and hence acts as a catalyst.
Therefore one mole of methane (from natural gas) reacts with one mole of steam, and compressed at $30{\text{ atm}}$ passed over Nickel at about ${800^ \circ }C$ to form syngas (a combination of one mole of carbon monoxide and three moles of hydrogen gas). The chemical equation for this reaction is written as follows:
$C{H_4} + {H_2}O\xrightarrow{{Nickel}}CO + 3{H_2}$

Note:
Nickel is a metal which is present in its solid form while steam and methane are there in the gaseous form. The reactants and the catalyst are in different states of matter therefore nickel acts as a heterogeneous catalyst in the given reaction.