`CH_3-CHO` is

Explanation

a.
b.
c. Syn `-` addition of `D,T`, and anti - Markovnikov's addition of `D` and , with being replaced by T(D and `T` are deuteriu and tritium, isotopes of H).

`d.`
`e.` Anti`-` and Markovnikov's addition of `(-H)` and `(-OH)`.

`f.` Anti`-` hydroxylation `:`

`g.` Syn `-` hydroxylation :
h. Anti `-` addition of `Br_(2):`

`i.` Anti`-` addition of `(-Br)` and `(-OH):`

`j.` Anti `-` addition of `I^(o+)` and `CI^(o+)` with Markovnikov's rule.

`k`. Addition of `H^(o+)` and `O^(c-)H` according to Markovnikov's rule , with rearrangements `(` if any `)`.
But `I` and `II` are the major products, since both have been formed from stable `3^(@)C^(c+)`.