A urea molecule contains
a.two nitrogen atoms
b.two carbon atoms
c.two hydrogen atoms
d.more than one correct response
e.no correct response
The correct answer and explanation is :
The correct answer is:
(a) Two nitrogen atoms
Explanation:
Urea ((\text{CH}_4\text{N}_2\text{O})) is a simple organic molecule that plays a crucial role in nitrogen metabolism in living organisms. It is the primary nitrogenous waste product in humans and many animals, excreted through urine.
1. Molecular Composition of Urea
Urea consists of:
- Two nitrogen (N) atoms
- One carbon (C) atom
- Four hydrogen (H) atoms
- One oxygen (O) atom
2. Structural Representation
The molecular formula of urea is CH₄N₂O, and its structural formula is:
[
\text{H}_2\text{N}-\text{C}(\text{=O})-\text{NH}_2
]
In this structure:
- The carbon atom is centrally located and forms a double bond with oxygen (C=O).
- Two amine (-NH₂) groups are attached to the carbon atom, each containing a nitrogen atom.
3. Evaluating the Answer Choices
- (a) Two nitrogen atoms → Correct
- Urea contains two nitrogen atoms from its two amine (-NH₂) groups.
- (b) Two carbon atoms → Incorrect
- Urea contains only one carbon atom, not two.
- (c) Two hydrogen atoms → Incorrect
- Urea has four hydrogen atoms (two from each -NH₂ group), not just two.
- (d) More than one correct response → Incorrect
- Only option (a) is correct, so this option does not apply.
- (e) No correct response → Incorrect
- Since (a) is correct, this option is not valid.
Thus, option (a) is the correct answer because a urea molecule contains two nitrogen atoms.