Select the correct statements of the following:-
(a) Effective nuclear charge for nitrogen is 3.90
(b) IP of Ne is more than `Na^(+)`
(c ) Order of electronegativity- `sp gt sp^(2) gt sp^(3)`
(d) Order of acidic character- `NH_(3) lt PH_(3) lt AsH_(3)`

Options

A. a, b, d
B. b, c
C. a, c, d
D. a, b, c, d

Answer

To solve the question, we need to evaluate each statement one by one and determine whether they are correct or not.

### Step 1: Evaluate Statement (a)
**Statement (a)**: Effective nuclear charge for nitrogen is 3.90.

- **Calculation**:
- The effective nuclear charge (Z_eff) can be calculated using the formula:
\[ Z_{\text{eff}} = Z - S \]
where \(Z\) is the atomic number and \(S\) is the shielding constant.
- For nitrogen (atomic number 7), the electronic configuration is \(1s^2 2s^2 2p^3\).
- The shielding constant \(S\) can be calculated as follows:
- For the outermost electrons (2p), the shielding contribution is \(0.35 \times 4\) (for the 4 electrons in the 2p orbital) + \(0.85 \times 2\) (for the 2 electrons in the 1s orbital).
- Thus, \(S = (0.35 \times 4) + (0.85 \times 2) = 1.4 + 1.7 = 3.1\).
- Now substituting back into the formula:
\[ Z_{\text{eff}} = 7 - 3.1 = 3.9 \]
- **Conclusion**: Statement (a) is correct.

### Step 2: Evaluate Statement (b)
**Statement (b)**: Ionization potential of Ne is more than Na⁺.

- **Analysis**:
- Neon (Ne) has the electronic configuration \(1s^2 2s^2 2p^6\), and Na⁺ has the electronic configuration \(1s^2 2s^2 2p^6\) as well.
- Both have a complete octet, but Na⁺ is a cation and has a higher effective nuclear charge due to the positive charge.
- Cations generally have higher ionization energies than neutral atoms because they are more stable and require more energy to remove an electron.
- **Conclusion**: Statement (b) is incorrect.

### Step 3: Evaluate Statement (c)
**Statement (c)**: Order of electronegativity - sp > sp² > sp³.

- **Analysis**:
- Electronegativity is directly proportional to the percentage of s-character in the hybrid orbitals.
- For sp hybridization, the s-character is 50%, for sp² it is 33%, and for sp³ it is 25%.
- Therefore, the order of electronegativity is indeed:
\[ \text{sp} > \text{sp}^2 > \text{sp}^3 \]
- **Conclusion**: Statement (c) is correct.

### Step 4: Evaluate Statement (d)
**Statement (d)**: Order of acidic character - NH₃ < PH₃ < AsH₃.

- **Analysis**:
- The acidic character of hydrides of group 15 decreases as we move down the group.
- NH₃ is a strong base and has the least acidic character, while AsH₃ is more acidic than PH₃.
- Therefore, the correct order of acidic character should be:
\[ \text{NH}_3 < \text{PH}_3 < \text{AsH}_3 \]
- **Conclusion**: Statement (d) is correct.

### Final Answer:
The correct statements are (a), (c), and (d). Therefore, the answer is option (a), (c), and (d).