A. oxygen and ozone B. but - I - ene and But2 - ene C. hydrogen and deuterium D. ortho hydrogen and para - hydrogen
Correct Answer: C
Explanation
- Oxygen \(\left(\mathrm{O}_2\right)\) and ozone \(\left(\mathrm{O}_3\right)\) are allotrope - But - I - ene and but - 2 - ene are isomers - Hydrogen \(\left({ }_1^1 \mathrm{H}\right)\) and deuterium \(\left({ }_1^2 \mathrm{H}\right)\) are isotopes - Ortho-hydrogen and para-hydrogen are allotropes
