The shapes of nitrite and nitrile respectively are:

Options

A. Linear and angular
B. Angular and linear
C. Both angular
D. Both linear

Answer

To determine the shapes of nitrite (NO₂⁻) and nitrile (CN⁻), we will follow these steps:

### Step 1: Identify the Chemical Structures
- **Nitrite Ion (NO₂⁻)**: The nitrite ion consists of one nitrogen atom and two oxygen atoms, with an overall negative charge.
- **Nitrile Ion (CN⁻)**: The nitrile ion consists of one carbon atom and one nitrogen atom, with an overall negative charge.

### Step 2: Draw the Lewis Structure for Nitrite (NO₂⁻)
1. Count the total number of valence electrons:
- Nitrogen (N) has 5 valence electrons.
- Each Oxygen (O) has 6 valence electrons, and there are two oxygens: 6 × 2 = 12.
- The negative charge adds 1 electron.
- Total = 5 + 12 + 1 = 18 valence electrons.

2. Arrange the atoms and distribute the electrons:
- Place nitrogen in the center and connect it to the two oxygen atoms.
- Form one double bond with one oxygen and a single bond with the other oxygen.
- Assign the remaining electrons to complete the octets.
- The structure will have one lone pair on nitrogen and one of the oxygens will carry the negative charge.

### Step 3: Determine the Hybridization of Nitrite
- The nitrogen atom in nitrite has:
- 2 single bonds (to oxygen) and 1 lone pair.
- Hybridization = Number of sigma bonds + Number of lone pairs = 2 + 1 = 3 (sp² hybridization).

### Step 4: Determine the Shape of Nitrite
- With sp² hybridization, the shape of nitrite is bent or angular due to the presence of the lone pair which repels the bonding pairs.

### Step 5: Draw the Lewis Structure for Nitrile (CN⁻)
1. Count the total number of valence electrons:
- Carbon (C) has 4 valence electrons.
- Nitrogen (N) has 5 valence electrons.
- The negative charge adds 1 electron.
- Total = 4 + 5 + 1 = 10 valence electrons.

2. Arrange the atoms and distribute the electrons:
- Carbon is connected to nitrogen with a triple bond (C≡N).
- All valence electrons are used in forming the triple bond.

### Step 6: Determine the Hybridization of Nitrile
- The carbon atom in nitrile has:
- 1 triple bond (to nitrogen).
- Hybridization = Number of sigma bonds + Number of lone pairs = 1 + 0 = 1 (sp hybridization).

### Step 7: Determine the Shape of Nitrile
- With sp hybridization, the shape of nitrile is linear.

### Conclusion
- The shapes of nitrite and nitrile respectively are:
- Nitrite: Angular (or bent)
- Nitrile: Linear

Thus, the correct answer is **Angular for nitrite and Linear for nitrile**.