Question

The catalyst used for the conversion of ethene to ethane is commonly:
A. Nickel
B. Iron
C. Cobalt
D. None of the above

Answer 1

Hint: This conversion reaction is known as hydrogenation. This catalyst is resistant to oxidation and corrosion. It is also used as alloy with another option in this question. It is used in corrosion-resistant alloys with copper. It is used as a protective coating on other metal by the process known as electroplating.

Step by step answer:
Ethene is an unsaturated alkene of molecular formula, \[~{{C}_{2}}{{H}_{4}}\] and that of ethane is a saturated alkane of molecular formula\[~{{C}_{2}}{{H}_{6}}\]. Conversion of an alkene to an alkane is a reduction reaction.
We should know that conversion of an unsaturated alkene-Ethene(\[~{{C}_{2}}{{H}_{4}}\]) to a saturated alkane-Ethane(\[~{{C}_{2}}{{H}_{6}}\]) involves a reduction process. We know this already that alkene contains a double bond which is substituted for with hydrogen atoms in an alkane in the reduction process. Basically, addition of hydrogen or removal of oxygen is a reduction process. Removal of hydrogen or addition of oxygen to a process is an oxidation process.
Therefore for conversion from Ethene to Ethane we have to look for a Reducing agent that will aid in the process.
We should know that hydrogenation is a chemical reaction between molecular hydrogen (\[{{H}_{2}}\]) and another compound or element, usually in the presence of a catalyst such as nickel.
So from the above discussion, we came to know that Nickel is used as a catalyst in hydrogenation reaction.
So, option A is correct.

Note: We use common catalysts that are insoluble metals such as palladium in the form Pd-C, platinum in the form Pt\[{{O}_{2}}\], and nickel in the form Ra-Ni. With the presence of a metal catalyst, the H-H bond in \[{{H}_{2}}\] cleaves, and each hydrogen attaches to the metal catalyst surface, forming metal-hydrogen bonds. The metal catalyst also absorbs the alkene onto its surface. A hydrogen atom is then transferred to the alkene, forming a new C-H bond. A second hydrogen atom is transferred forming another C-H bond. At this point, two hydrogen have added to the carbons across the double bond. Because of this alkene transforms into alkane.
We use hydrogenation in the food industry to make a large variety of manufactured goods, like spreads and shortenings, from liquid oils. This process also increases the chemical stability of products and yields semi-solid products like margarine. Hydrogenation is also used in coal processing.