The number of HNMR signals a molecule gives depends on the number of DIFFERENT HYDROGENS the molecule has. What does different means? 2 Hydrogens are different if the carbons they are attached to have a point of difference as we go to the left and to the right. Therefore the more symmetrical a molecule is, the more SAME Hydrogens it has, and the less signals it will give you.
How many HNMR signals does cyclohexane have?
A 1 B 3 C 6 D 12
Cyclohexane has only one HNMR signal because all of its hydrogens are the same. The molecule is highly symmetrical, and if we check any hydrogens, their carbons will have exactly the same connections (connected to two CH2 groups)