The total number of lone - pairs of electrons and `sp^3` hybridized nitrogen atoms in melamine are respectively

Options

A. 6,6
B. 3,3
C. 6,3
D. 3,6

Answer

To solve the question regarding the total number of lone pairs of electrons and `sp^3` hybridized nitrogen atoms in melamine, we will follow these steps:

### Step 1: Understand the Structure of Melamine
Melamine is a compound with the formula C3H6N6. Its structure consists of a triazine ring (a six-membered ring with alternating double bonds) and three amine groups (-NH2) attached to the ring.

### Step 2: Draw the Structure
The structure of melamine can be represented as follows:

```
N
// \
N N
// \\
H2N N
\ /
H2N--H2N
```

### Step 3: Identify the Nitrogen Atoms
In the structure, we can identify a total of 6 nitrogen atoms. They are arranged in a way that some are involved in double bonds while others are bonded to hydrogen atoms.

### Step 4: Determine Hybridization of Nitrogen Atoms
- **`sp^3` Hybridized Nitrogens**:
- The nitrogen atoms that are bonded to two hydrogen atoms and one carbon atom (the amine groups) are `sp^3` hybridized.
- Each of these nitrogen atoms has one lone pair of electrons.

- **`sp^2` Hybridized Nitrogens**:
- The nitrogen atoms that are part of the double bonds in the triazine ring are `sp^2` hybridized. They do not have lone pairs because they are involved in double bonding.

### Step 5: Count the `sp^3` Hybridized Nitrogens
From the structure, we can see that there are 3 nitrogen atoms that are `sp^3` hybridized (the ones attached to the -NH2 groups).

### Step 6: Count the Total Lone Pairs
- Each of the 3 `sp^3` hybridized nitrogen atoms has 1 lone pair.
- The 3 `sp^2` hybridized nitrogen atoms do not have any lone pairs.
- Therefore, the total number of lone pairs is:
- 3 (from `sp^3` nitrogen) + 3 (from the nitrogen in the ring, as each has 1 lone pair) = 6 lone pairs.

### Conclusion
The total number of lone pairs of electrons and `sp^3` hybridized nitrogen atoms in melamine are respectively:
- **Lone pairs**: 6
- **`sp^3` hybridized nitrogen atoms**: 3

Thus, the answer is **6 and 3**.

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