A sample of liquid \(\mathrm{NH}_{3}\) is brought to its boiling point. Which of the following occurs during the boiling process? (A) The N-H bonds within the NH_{3} \text { molecules break apart. } (B) The overall temperature of the solution rises as the NH, molecules speed up. (C) The amount of energy within the system remains constant. (D) The hydrogen bonds holding separate \(\mathrm{NH}_{3}\) molecules together break apart.

In a boiling process, a substance changes from the liquid phase to the gaseous phase. This process requires an addition of energy to provide the molecules with enough kinetic energy to overcome their intermolecular forces. Boiling doesn't affect the temperature, instead, energy is used for this phase transition.

(A) The N-H bonds within the NH3 molecules break apart. - In the boiling process, the energy supplied typically doesn't break chemical bonds, instead, it overcomes the intermolecular forces. So, this option is incorrect. \n(B) The overall temperature of the solution rises as the NH3 molecules speed up. - The temperature remains constant during boiling, so this option is incorrect. \n(C) The amount of energy within the system remains constant. - Energy is added to the system in the form of heat during boiling, so this option is incorrect. \n(D) The hydrogen bonds holding separate NH3 molecules together break apart. - This is indeed what happens during boiling; the intermolecular forces (in this case, hydrogen bonds) are broken. Hence, this is the correct choice.

Only option D aligns with the understanding of the boiling process. The boiling process for NH3 involves breaking the hydrogen bonds between the NH3 molecules.