Question 17.6.3: The following compounds show only one signal in the NMR spec......
The following compounds show only one signal in the NMR spectrum. Write their structural formulae
(a) C_5H_{12} (b) C_2H_6O (c) C_2H_4Br_2 (d) C_4H_6
(a) C_5H_{12} Single signal means that all the 12 hydrogen atoms are equivalent. Hence, the molecule contains four equivalent methyl groups. Hence its structure is
\begin{matrix} & & CH_3 & &\\ & & | & & \\H_3C &—& C&—&CH_3\\ & & | & & \\ & & CH_3 & & \end{matrix}
(b) C_2H_6O Single signal can be accounted for by two equivalent CH_3 groups. Hence, the structure is
CH_3 – O – CH_3(c) C_2H_4Br_2 It will have two equivalent methylene groups. Hence the probable structure is
Br – CH_2 – CH_2 – Br(d) C_4H_6 Single signal can be explained by considering that the molecule has two methyl groups and the two carbon atoms are without hydrogen.
H_3C – C≡ C – CH_3.