Which of the following is least ionic ?

Options

A. `AgCl`
B. `KCI`
C. `BaCl_2`
D. `CaCl_2`

Answer

To determine which compound among KCl, CaCl2, BaCl2, and AgCl is least ionic, we can follow these steps:

### Step 1: Understand Ionic Character
Ionic character in a compound is influenced by the difference in electronegativity between the cation (positive ion) and the anion (negative ion). A larger difference in electronegativity generally indicates a more ionic bond.

### Step 2: Identify the Anion
In all the given compounds (KCl, CaCl2, BaCl2, AgCl), the anion is chlorine (Cl). Since the electronegativity of chlorine is constant across these compounds, we only need to focus on the cations.

### Step 3: Identify the Cations
The cations in the compounds are:
- K+ (from KCl)
- Ca2+ (from CaCl2)
- Ba2+ (from BaCl2)
- Ag+ (from AgCl)

### Step 4: Compare Electropositivity
Electropositivity refers to the ability of an element to donate electrons and form positive ions. In the periodic table:
- Potassium (K) is an alkali metal and is highly electropositive.
- Calcium (Ca) and Barium (Ba) are alkaline earth metals and are also quite electropositive, but less than alkali metals.
- Silver (Ag) is a d-block element and is less electropositive compared to the alkali and alkaline earth metals.

### Step 5: Determine Ionic Character
Since K+, Ca2+, and Ba2+ are more electropositive than Ag+, the compounds KCl, CaCl2, and BaCl2 will have a higher ionic character compared to AgCl. Therefore, AgCl, which has a less electropositive cation (Ag+), will exhibit the least ionic character.

### Conclusion
Among the given options, AgCl is the compound with the least ionic character.

### Final Answer
**AgCl has the least ionic character.**

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