Isomer counts and degree of unsaturation of drawn compounds

13 questions on Isomer counts and degree of unsaturation of drawn compounds from the IUPAC Nomenclature and Structural Isomerism chapter: 2 NEET level, 5 JEE Main, 6 JEE Advanced. Each one opens with its answer and solution.

• What is the degree of unsaturation (rings plus pi bonds) of the compound shown? NEET level, drawn structure
• How many different monochlorination products (monochloroalkanes) can the alkane shown give? Count constitutional isomers only and ignore stereoisomers. NEET level, drawn structure
• Which of the structures shown is a structural isomer of the compound shown? JEE Main level, drawn structure
• Which of the structures shown is a ring-chain isomer of the compound shown? JEE Main level, drawn structure
• How many different monochlorination products can the alkane shown give? Count constitutional isomers only and ignore stereoisomers. JEE Main level, drawn structure
• What is the degree of unsaturation of the compound shown? Use the formula (2C + 2 + N - H - X)/2, where X is the number of halogen atoms. JEE Main level, drawn structure
• Which of the structures shown are isomers (same molecular formula) of the compound shown? JEE Main level, drawn structure
• The compound shown has the molecular formula C4H10O. Counting the compound shown itself, how many acyclic structural isomers (alcohols and ethers) have this for... JEE Advanced level, drawn structure
• The compound shown has the molecular formula C5H10O. How many acyclic structural isomers of this formula contain a single C=O group (aldehydes and ketones), cou... JEE Advanced level, drawn structure
• Which of the following statements about the compound shown are correct? Count constitutional isomers only and ignore stereoisomers. JEE Advanced level, drawn structure
• How many stereoisomers (configurational isomers, optical and geometrical together, counting a meso form once) does the constitution shown have? JEE Advanced level, drawn structure
• The compound shown is completely hydrogenated (H2, Ni) to an alkane. How many different monochlorination products can that alkane give? Count constitutional iso... JEE Advanced level, drawn structure
• The compound shown has the molecular formula C5H10. How many structural isomers of this formula exist in total, counting both acyclic (alkenes) and cyclic (cycl... JEE Advanced level, drawn structure