Question

1−Butene may be converted to butane by reaction with:
(A)Zn-HCl
(B)Sn-HCl
(C)Zn-Hg
(D)$Pd/{{H}_{2}}$

Answer 1

Hint: As we can see that 1−Butene needs to be converted to butane which means addition of 2 hydrogen atoms i.e., reduction of 1−Butene. So we may require a reagent which acts as a reducing agent for 1−Butene and into its respective alkane. We may attempt this question by checking the properties of each reagent given in the option.

Complete step-by-step answer: Reagents are the chemical substances that are added to other compounds to cause a chemical reaction. There are many reagents and few of them are as follows:-

-Zn-HCl: Generally the function of Zn-HCl is covert alkyl halide to alkane. When zinc is added in hydrochloric acid, the reaction bubbles vigorously as hydrogen gas is liberated. The production of a hydrogen gas is also an indication that a chemical reaction is occurring and it replaces halogen from alkyl halide to convert it into alkane.
-Sn-HCl: This reagent can be used for various purposes such as conversion of nitro compounds to amines. It is also used to convert alkyl halides and halo cycloalkane to alkanes and cycloalkanes respectively. Here, tin (Sn) reacts with hydrochloric acid to form Tin (IV) chloride and the ${{H}^{+}}$ reacts with the nitro compounds to give amines as product.
- Zn-Hg: This reagent is very famous for the reduction of carbonyl compounds to their respective alkanes in presence of concentrated hydrochloric acid. This is also known as Clemmensen Reduction.
-$Pd/{{H}_{2}}$: This reagent is used for the Hydrogenation reaction in which C=C pi bonds are broken and replaced by C-H sigma bonds. We can also say that it is a process to convert unsaturated fats to saturated fats. This reagent helps in addition of ${{H}_{2}}$ gas to alkenes and converts them into alkanes
-From the above data we can conclude that (D) $Pd/{{H}_{2}}$ is used to convert 1-Butene to butane as shown below:-
\[C{{H}_{2}}=CHC{{H}_{2}}C{{H}_{3}}\xrightarrow{Pd/{{H}_{2}}}C{{H}_{3}}C{{H}_{2}}C{{H}_{2}}C{{H}_{3}}\]

Note: -When $Pd/{{H}_{2}}$ is used on alkenes, it adds in syn manner i.e., from the same side or face of the alkenes.
-It is also used to convert alkynes to alkanes (requires 2 equivalents of $Pd/{{H}_{2}}$). It can also reduce nitriles, imines and nitro groups to amines. It is a very good reducing agent and hence converts benzene rings to cyclohexane.