Question

How much energy is transferred when 1l of boiling water at 100 k condenses to water at 100 k?

Answer 1

water doesn't boil at 100K. It boils at 100°C. And when water is at 100°C, it will be boiling. So boiling water at 100°C and water at 100°C are the same. There is no energy transfer.

Answer 2

Water boils at 100°C, not at 100K. And, boiling water at 100°C and water at 100°C are the same. There will be no energy transfer.