Which one of the following compounds has bond angle close to `90^@` ?

Options

A. `H _(2)O`
B. `H_(2)S`
C. `NH_(3)`
D. `CH_(4)`

Answer

To determine which of the given compounds has a bond angle close to 90 degrees, we will analyze the molecular geometry and bond angles of each compound: water (H2O), hydrogen sulfide (H2S), ammonia (NH3), and methane (CH4).

### Step 1: Analyze Water (H2O)
- Water has two hydrogen atoms bonded to an oxygen atom.
- The molecular geometry is bent due to the presence of two lone pairs on the oxygen atom.
- The bond angle in water is approximately 104.5 degrees.

**Hint:** Consider the number of lone pairs and bond pairs when determining the molecular shape.

### Step 2: Analyze Hydrogen Sulfide (H2S)
- Hydrogen sulfide has two hydrogen atoms bonded to a sulfur atom.
- Similar to water, H2S has two lone pairs on the sulfur atom, resulting in a bent molecular geometry.
- The bond angle in H2S is approximately 92 degrees, which is closer to 90 degrees than water.

**Hint:** Compare the electronegativity of the central atom to understand the impact on bond angles.

### Step 3: Analyze Ammonia (NH3)
- Ammonia has three hydrogen atoms bonded to a nitrogen atom.
- It has one lone pair on the nitrogen atom, leading to a trigonal pyramidal shape.
- The bond angle in ammonia is approximately 107 degrees.

**Hint:** Remember that lone pairs can affect bond angles by repelling bonding pairs.

### Step 4: Analyze Methane (CH4)
- Methane has four hydrogen atoms bonded to a carbon atom.
- There are no lone pairs on the carbon atom, resulting in a tetrahedral geometry.
- The bond angle in methane is approximately 109.5 degrees.

**Hint:** Tetrahedral shapes have larger bond angles due to the absence of lone pairs.

### Conclusion
Among the compounds analyzed, hydrogen sulfide (H2S) has the bond angle closest to 90 degrees, approximately 92 degrees. Therefore, the correct answer is:

**Answer:** H2S