Final answer:
To calculate the unsaturation number for C6H10O, compare it to a saturated alkane with the same carbon count, C6H14. The difference in hydrogen atoms indicates two degrees of unsaturation, giving an answer of B) 2.
Step-by-step explanation:
The unsaturation number, or index of hydrogen deficiency (IHD), is a way to determine the number of double bonds, triple bonds, and rings in a compound based on its molecular formula. For alkanes, the general formula is CnH2n+2, where n represents the number of carbon atoms. To calculate the IHD for a compound with the formula C6H10O, we first find the number of hydrogens in a saturated alkane with the same number of carbon atoms, which is C6H14. Subtracting the actual number of hydrogens in the compound from the number in the saturated alkane gives us a difference of 4 hydrogen atoms (14 - 10 = 4). A difference of 4 hydrogen atoms implies an IHD of 2 because each degree of unsaturation accounts for 2 fewer hydrogens. As such, the answer is B) 2, as the compound has two degrees of unsaturation.