If S and V are the change in surface area and volume, when two soap bubbles coalesce under isothermal condition, then (σ is surface tension, Po is atmospheric pressure)
Let a and b be the radius of two soap bubbles forming a soap bubble of radius c. Then
(Po+4σa)43πa3+43πb3(Po+4σb)=(Po+4σc)43πc3
i.e., Po[43π(a3+b3−c3)]=4σ[43π(c2−a2−b2)]
PoV=−4σS3
3PoV+4σS=0
So choice (1) is correct and the rest are wrong