Question

Two soap bubbles coalesce to form a single large bubble. :

Answer 1

On joining the 2 drops, the total surface area decreases. As a result, the surface energy of the system will decrease.

Now, on joining, the 2 drops the volume remains constant, however, the larger bubble will have a larger radius. As a result, it will have a lesser inside pressure. Therefore, we can say that the pressure in the larger bubble decrease.

Now, since, the volume remains constant and the pressure decrease, therefore, the temperature will also decrease.

Hence, all the 3 parameters will decrease on joining the 2 bubbles