Chapter 10, Problem 10.63AP

Interpretation Introduction

Interpretation:

The structure of an alkane, an alkene and an alkyne each having five carbon atoms has to be drawn and molecular formula of each compound has to be explained.

Concept Introduction:

Alkanes:

The alkanes are simple organic compounds.  These alkane compounds have carbon-carbon single bond and it is not a functional group.  The alkanes are saturated compounds.  The molecular formula of alkane compounds can be given as ${\text{C}}_{\text{n}}{\text{H}}_{\text{2n+2}}$ where, n refers to number of carbon atom present in alkane compound.  The root name of alkane compounds are given as –ane.

Alkenes:

The alkene compounds have their functional group as carbon–carbon double bonds.  The alkene groups are known as unsaturated compounds.  The molecular formula of alkene compounds is given as ${\text{C}}_{\text{n}}{\text{H}}_{\text{2n}}$.  The root name of alkene compounds are given as –ene.

Alkyne:

The alkyne compounds have their functional group as carbon-carbon triple bonds.  The alkene compounds are known as unsaturated hydrocarbons.  The molecular formula of alkyne compounds is given as ${\text{C}}_{\text{n}}{\text{H}}_{\text{2n}}{}_{\text{-2}}$.  The root name of alkyne compound is given as –yne.

Explanation of Solution

The structure of an alkane compound having five carbon atoms has to be drawn.  The alkane compounds have carbon-carbon single bond.  The first step is to draw the carbon skeleton having five carbon atoms for an alkane compound.  Then add hydrogen atom to the carbon in the chain.  The carbon belongs to group 4A of periodic table.  The carbon has four valence electrons.  So the carbon should have four bonds.

The alkane compound having five carbon atoms is drawn below,

The structure of an alkene compound having five carbon atoms has to be drawn.  The alkene compounds have carbon-carbon double bond.  The first step is to draw the carbon skeleton having five carbon atoms for an alkene compound.  The double bond is bonded between second and third carbon atoms.  Then add hydrogen atom to the carbon in the chain.  The carbon belongs to group 4A of periodic table.  The carbon has four valence electrons.  So the carbon should form four bonds.

The alkene compound having five carbon atoms is drawn below,

The structure of an alkyne compound having five carbon atoms has to be drawn.  The alkyne compounds have carbon-carbon triple bond.  The first step is to draw the carbon skeleton having five carbon atoms for an alkyne compound.  The triple bond is bonded between second and third carbon atoms.  Then add hydrogen atom to the carbon in the chain.  The carbon belongs to group 4A of periodic table.  The carbon has four valence electrons.  So the carbon should form four bonds.

The alkyne compound with five carbon atoms is drawn below,

The molecular formula of alkane compound having five carbon atoms is given as,

The molecular formula of alkane compounds can be given as ${\text{C}}_{\text{n}}{\text{H}}_{\text{2n+2}}$.  It has to be multiplied by 2 and the answer has to be sum by 2.  Hence the molecular formula of pentane compound can be given as ${\text{C}}_{\text{5}}{\text{H}}_{\text{12}}$.

Given: $\text{n=}\text{5}$

$\begin{array}{l}\text{The}\text{molecular}\text{formula}\text{of}\text{alkane}\text{=}{\text{C}}_{\text{n}}{\text{H}}_{\text{2n+2}}\\ \text{=}{\text{C}}_{\text{5}}{\text{H}}_{\text{2×5+2}}\\ \text{=}{\text{C}}_{\text{5}}{\text{H}}_{\text{12}}\end{array}$

The molecular formula of alkene compound having five carbon atoms is given below,

The molecular formula of alkene compounds can be given as ${\text{C}}_{\text{n}}{\text{H}}_{\text{2n}}$.  The number of carbon atom has to be multiplied by 2.  If the number of carbon is 5, then gives ten hydrogen atoms.  Hence the molecular formula of pentene can be given as ${\text{C}}_{\text{5}}{\text{H}}_{10}$.

Given: $\text{n=}\text{5}$

$\begin{array}{l}\text{The}\text{molecular}\text{formula}\text{of}\text{alkane}\text{=}{\text{C}}_{\text{n}}{\text{H}}_{\text{2n}}\\ \text{=}{\text{C}}_{\text{5}}{\text{H}}_{\text{2×5}}\\ \text{=}{\text{C}}_{\text{5}}{\text{H}}_{\text{10}}\end{array}$

The molecular formula of alkyne compound having five carbon atoms is given below,

The molecular formula of alkyne compounds are given as ${\text{C}}_{\text{n}}{\text{H}}_{\text{2n}}{}_{\text{-2}}$.  It has to be multiplied by 2 and then subtracted by 2.  If the number of carbon is 5 it gives eight hydrogen atoms.  Hence the molecular formula of pentyne can be given as ${\text{C}}_{\text{5}}{\text{H}}_8$.

Given: $\text{n=}\text{5}$

$\begin{array}{l}\text{The}\text{molecular}\text{formula}\text{of}\text{alkane}\text{=}{\text{C}}_{\text{n}}{\text{H}}_{\text{2n}}\\ \text{=}{\text{C}}_{\text{5}}{\text{H}}_{\text{2×5}}{}_{\text{-2}}\\ \text{=}{\text{C}}_{\text{5}}{\text{H}}_{\text{10-2}}\\ \text{=}{\text{C}}_{\text{5}}{\text{H}}_{\text{8}}\end{array}$