An organic compound with the formula ${\text{C}}_{\text{10}}{\text{H}}_{\text{8}}$ absorbs 5 moles of ${\mathrm{H}}_2$ during hydrogenation. The number of rings present in it is 

•  Organic compound naphthalene has the molecular formula ${\text{C}}_{\text{10}}{\text{H}}_{\text{8}}$. 
• It has two fused benzene rings and is a polycyclic aromatic hydrocarbon.
• It is a crystalline white substance. 
• There are single bonds and alternative double bonds.
•  As a result, the bond lengths fluctuate along with the hybridization. The naphthalene structure is also subject to resonance. 

Therefore, the number of rings of an organic compound is 2