The compound which contains both ionic and covalent bonds is

Options

A. KCN
B. KCl
C. `K_(2)S`
D. `H_(2)O_(2)`

Answer

To determine which compound contains both ionic and covalent bonds, we will analyze each option based on the electronegativity differences between the atoms involved in the bonds.

### Step-by-Step Solution:

1. **Understand the Types of Bonds:**
- Ionic bonds form when the electronegativity difference between two atoms is equal to or greater than 1.7.
- Covalent bonds form when the electronegativity difference is less than 1.7.

2. **Analyze Option 1: KCN (Potassium Cyanide)**
- Potassium (K) has an electronegativity of approximately 0.8.
- Carbon (C) has an electronegativity of approximately 2.5.
- The electronegativity difference between K and C is:
\[ 2.5 - 0.8 = 1.7 \]
This indicates an ionic bond.
- Nitrogen (N) has an electronegativity of approximately 3.0.
- The electronegativity difference between C and N is:
\[ 3.0 - 2.5 = 0.5 \]
This indicates a covalent bond.
- Therefore, KCN contains both ionic (K-C) and covalent (C-N) bonds.

3. **Analyze Option 2: KCl (Potassium Chloride)**
- Chlorine (Cl) has an electronegativity of approximately 3.0.
- The electronegativity difference between K and Cl is:
\[ 3.0 - 0.8 = 2.2 \]
This indicates an ionic bond.
- KCl contains only ionic bonds.

4. **Analyze Option 3: K2S (Potassium Sulfide)**
- Sulfur (S) has an electronegativity of approximately 2.5.
- The electronegativity difference between K and S is:
\[ 2.5 - 0.8 = 1.7 \]
This indicates an ionic bond.
- K2S contains only ionic bonds.

5. **Analyze Option 4: H2O2 (Hydrogen Peroxide)**
- The electronegativity of hydrogen (H) is approximately 2.1, and for oxygen (O), it is approximately 3.5.
- The electronegativity difference between O and H is:
\[ 3.5 - 2.1 = 1.4 \]
This indicates a covalent bond.
- H2O2 contains only covalent bonds.

### Conclusion:
- The only compound that contains both ionic and covalent bonds is **KCN** (Potassium Cyanide).

### Final Answer:
The compound which contains both ionic and covalent bonds is **KCN**.