Final answer:
The H-NMR chemical shift range for alkanes is typically between 0.9 to 1.5 ppm, with variations depending on the specific hydrogen environments within the alkane.
Step-by-step explanation:
The H-NMR chemical shift range for alkanes typically falls between 0.9 to 1.5 parts per million (ppm). In H-NMR spectroscopy, the chemical shifts are measured relative to a standard, usually tetramethylsilane (TMS), which is assigned a chemical shift of zero ppm. Since alkanes are saturated hydrocarbons with only single bonds between carbon atoms, their hydrogen atoms are in a relatively non-electronegative environment, leading to this upfield (lower) shift range.
Different hydrogen environments within the alkane can cause slight variations within this range. For example, a methyl group attached to a primary carbon may have a shift around 0.9 ppm, while a methyl group attached to a quaternary carbon may shift closer to 1.5 ppm.