Video narration
How do you predict whether ozonolysis gives an aldehyde, ketone, carboxylic acid, or even CO2? Use the same atom-by-atom bookkeeping you use with structural formulas. First, split the C=C. Stop reading the alkene as one molecule: inspect each alkene carbon independently. Each one becomes a carbonyl carbon, keeping its original substituents. Now check hydrogen. If that carbon had hydrogen, it becomes an aldehyde under reductive workup-Zn/H2O or (CH3)2S. If it had no hydrogen, it becomes a ketone. Then apply the second branch. With oxidative workup, H2O2, every aldehyde is pushed further to a carboxylic acid, while ketones stay unchanged. One JEE trap: a terminal =CH2 carbon gives formaldehyde in reductive conditions, but CO2 under oxidative workup. So don't memorise the whole molecule. Track each alkene carbon: no H means ketone; H means aldehyde reductively, acid oxidatively-and terminal carbon means CO2. That's the answer.