Step 1: Write the structure of 2-Methylbuta-1,3-diene.
2-Methylbuta-1,3-diene is also called isoprene.
Its structure is
\[
CH_2=C(CH_3)-CH=CH_2
\]
Step 2: Understand ozonolysis of double bonds.
Ozonolysis breaks each carbon-carbon double bond and converts the double-bonded carbon atoms into carbonyl compounds.
The molecule contains two double bonds:
\[
CH_2=C(CH_3)
\]
and
\[
CH=CH_2
\]
Step 3: Cleavage of the first double bond.
On cleavage of the double bond
\[
CH_2=C(CH_3)-
\]
the terminal carbon gives
\[
HCHO
\]
which is methanal.
The substituted carbon remains connected to the middle carbon and becomes part of a keto-aldehyde fragment.
Step 4: Cleavage of the second double bond.
On cleavage of the double bond
\[
-CH=CH_2
\]
the terminal carbon again gives
\[
HCHO
\]
which is methanal.
The remaining middle fragment forms
\[
CH_3COCHO
\]
which is 2-ketopropanal.
Step 5: Write the overall products.
Thus,
\[
CH_2=C(CH_3)-CH=CH_2
\]
on ozonolysis gives
\[
2HCHO + CH_3COCHO
\]
That is,
\[
2\ \text{moles of methanal} + 1\ \text{mole of 2-ketopropanal}
\]
Step 6: Final conclusion.
Therefore,
\[
\boxed{\text{2 moles of methanal and 1 mole of 2-ketopropanal}}
\]
Hence, the correct option is (2).