Question

Three organic compounds A, B and C have the following molecular formulae:

1. C₄H₈O₂
2. CH₁₀O
3. С₄H₈O

1. Which compound contains an alcohol group? Write its name and structural formula.
2. Which compound contains a carboxyl group? Write its name and structural formula.
3. Which molecular formula can represent an aldehyde as well as a ketone? Write the names and structural formulae of the aldehyde and ketone represented by this molecular formula.

Answer 1

a. B: Butanol (C₄H₉OH)

\[\begin{array}{cc}
\ce{H}\phantom{....}\ce{H}\phantom{.....}\ce{H}\phantom{....}\ce{H}\phantom{..}\\
|\phantom{......}|\phantom{......}|\phantom{......}|\phantom{..}\\
\ce{H - C - C - C - C - OH}\\
|\phantom{......}|\phantom{......}|\phantom{......}|\phantom{..}\\
\ce{H}\phantom{....}\ce{H}\phantom{.....}\ce{H}\phantom{....}\ce{H}\phantom{..}\\
\end{array}\]

b. A: Butanoic acid (C₃H₇COOH)

\[\begin{array}{cc}
\ce{H}\phantom{....}\ce{H}\phantom{.....}\ce{H}\phantom{.....}\ce{O}\phantom{..}\\
|\phantom{......}|\phantom{......}|\phantom{......}||\phantom{..}\\
\ce{H - C - C - C - C - OH}\\
|\phantom{......}|\phantom{......}|\phantom{..........}\\
\ce{H}\phantom{....}\ce{H}\phantom{.....}\ce{H}\phantom{..........}\\
\end{array}\]

c. C₄H₈O

Aldehyde: Butanal (C₃H₇CHO)

\[\begin{array}{cc}
\phantom{.}\ce{H}\phantom{....}\ce{H}\phantom{.....}\ce{H}\phantom{.....}\ce{O}\\
\phantom{.}|\phantom{......}|\phantom{......}|\phantom{......}||\\
\ce{H - C - C - C - C - H}\\
\phantom{...}|\phantom{......}|\phantom{......}|\phantom{..........}\\
\phantom{...}\ce{H}\phantom{....}\ce{H}\phantom{.....}\ce{H}\phantom{..........}\\
\end{array}\]

Ketone: Butanone (CH₃COCH₂CH₃)

\[\begin{array}{cc}
\phantom{.}\ce{H}\phantom{....}\ce{O}\phantom{....}\ce{H}\phantom{.....}\ce{O}\\
\phantom{.}|\phantom{.....}||\phantom{......}|\phantom{......}|\\
\ce{H - C - C - C - C - H}\\
\phantom{..........}|\phantom{.............}|\phantom{......}|\phantom{..........}\\
\phantom{..........}\ce{H}\phantom{...........}\ce{H}\phantom{.....}\ce{H}\phantom{..........}\\
\end{array}\]