The order of basicity of hydroxides of alkali metals is

Options

A. `LigtNagtRbgtCs`
B. `NagtLigtRbgtCs`
C. `CsgtRbgtNagtLi`
D. `RbgtCsgtNagtLi`

Answer

To determine the order of basicity of hydroxides of alkali metals, we follow these steps:

### Step 1: Identify the alkali metals
The alkali metals are located in Group 1 of the periodic table. The elements in this group are:
- Lithium (Li)
- Sodium (Na)
- Potassium (K)
- Rubidium (Rb)
- Cesium (Cs)

### Step 2: Understand the concept of basicity
Basicity refers to the ability of a substance to accept protons (H⁺ ions) or donate hydroxide ions (OH⁻). In the case of alkali metal hydroxides, they dissociate in water to produce hydroxide ions.

### Step 3: Analyze the trend in electropositivity
As we move down the group from lithium to cesium, the size of the alkali metal atoms increases, and their electropositivity also increases. Electropositivity is the tendency of an atom to lose its outermost electron and form positive ions.

### Step 4: Relate electropositivity to basicity
Higher electropositivity means that the alkali metal can more easily donate its hydroxide ion (OH⁻) in solution. Therefore, the basicity of the hydroxides increases as we move down the group.

### Step 5: Establish the order of basicity
Based on the increasing electropositivity and the ability to donate hydroxide ions, the order of basicity of alkali metal hydroxides is:
- Cesium hydroxide (CsOH) > Rubidium hydroxide (RbOH) > Potassium hydroxide (KOH) > Sodium hydroxide (NaOH) > Lithium hydroxide (LiOH)

### Final Order of Basicity
Thus, the order of basicity of hydroxides of alkali metals is:
**CsOH > RbOH > KOH > NaOH > LiOH**