بايو بايت - BioByte

From the following question the most stable compound is

From the previous question the most stable compound is

The least stable compound is

The most two stable compounds from the previous picture is

The less stable compound among these two compounds is

Which more stable if we consider that number 2 doesn’t go under resonance

What is the major product formed from the reaction of Propyne (CH_3-C \equiv CH) with H_2SO_4 / HgSO_4 / H_2O?