Exams › JEE Advanced › Chemistry

In a healthy adult human (75 kg), hydrogen accounts for 10.0% of body mass. If all ordinary hydrogen atoms (mass 1 u) are replaced by deuterium atoms (mass 2 u), what mass does the person gain?

1. 15 kg
2. 37.5 kg
3. 7.5 kg
4. 10 kg

Correct answer: 7.5 kg

Solution

Mass of hydrogen in body = 10% * 75 kg = 7.5 kg. Replacing ¹H (mass 1 u each) with ²H (mass 2 u each) means each atom gains 1 u, effectively doubling the mass of all hydrogen atoms. Mass gained = 7.5 kg.

Related JEE Advanced Chemistry questions

• Which of the following contains the highest number of molecules?
• An organic compound with identical empirical and molecular formulas consists of 20% carbon, 6.7% hydrogen, 46.7% nitrogen, and the remainder as oxygen. When heated, it releases ammonia and leaves behind a solid residue. This residue produces a violet color when treated with an alkaline copper sulfate solution. Identify the compound.
• Which of the following statements accurately describe a hydrogen peroxide solution with a concentration of 17 g/L?
• The total energy needed to break all three P−H bonds in PH3(g) is 954 kJ mol⁻¹. What is the energy required to break a single P−H bond?
• Which of the following represents the balanced equation for the Calvin cycle in photosynthesis, showing the conversion of carbon dioxide into glucose?
• A substance H₂X with a molecular mass of 80 g is mixed into a liquid with a density of 0.4 g/ml. If the volume remains constant during dissolution, what is the molality of a solution with 3.2 molarity?

⚔️ Practice JEE Advanced Chemistry free + battle 1v1 →