The correct order of reducing character of alkali metals is

Options

A. `Rb lt K lt Na lt Li`
B. `Li lt Na lt K lt Rb`
C. `Na lt K lt Rb lt Li`
D. `Rb lt Na lt K lt Li`.

Explanation

To determine the correct order of reducing character of alkali metals, we need to consider the general trend in reducing strength as we move down the group in the periodic table. Here’s a step-by-step solution:

### Step 1: Understand Reducing Character
Reducing character refers to the ability of an element to donate electrons. The stronger the reducing agent, the more readily it can lose electrons.

### Step 2: Identify the Alkali Metals
The alkali metals include lithium (Li), sodium (Na), potassium (K), rubidium (Rb), and cesium (Cs).

### Step 3: Recognize the Trend in Reducing Strength
As we move down the group from lithium to cesium, the reducing character generally increases. This is because the atomic size increases, leading to a decrease in ionization energy, making it easier for the metals to lose their outermost electron.

### Step 4: Consider Exceptions
While the trend indicates that reducing strength increases down the group, lithium is an exception due to its high electronegativity and the relatively high ionization energy compared to other alkali metals. Therefore, lithium does not behave as a strong reducing agent compared to sodium, potassium, rubidium, and cesium.

### Step 5: Arrange the Alkali Metals in Order of Reducing Character
Based on the above points, the order of reducing character from weakest to strongest is:
- Lithium (Li) < Sodium (Na) < Potassium (K) < Rubidium (Rb) < Cesium (Cs)

### Conclusion
Thus, the correct order of reducing character of alkali metals is:
**Li < Na < K < Rb < Cs**