Question

Using data from the Table, answer the following:

Examples	C2H6 Ethane	C2H4 Ethene	C2H2 Ethyne
Structure	\[\begin{array}{cc} \backslash \phantom{......}/\phantom{.}\\ \ce{—C – C —}\\  /\phantom{......}\backslash\phantom{.}\end{array}\]	\[\begin{array}{cc} \backslash \phantom{......}/\\ \ce{C \text{=} C}\\  /\phantom{......}\backslash\end{array}\]	\[\ce{- C ≡ C -}\]
Type of bond between carbons	single	double	triple
Bond length (nm)	0.154	0.134	0.120
Bond Enthalpy kJ mol-1	348	612	837

1. What happens to the bond length when unsaturation increases?
2. Which is the most stable compound?
3. Indicate the relationship between bond strength and Bond enthalpy.
4. Comment on the overall relation between Bond length, Bond Enthalpy, and Bond strength and stability.

Answer 1

1. When unsaturation increases, the bond length decreases.
2. The stable compound is ethyne (C₂H₂).
3. Bond strength `prop` Bond enthalpy Larger the bond enthalpy, the stronger is the bond.
4. As bond length decreases, bond enthalpy, bond strength, and stability increase.