In group 14 of the periodic table, the oxidising power of tetravalent species decreases in the order
a. `Ge gt Pb gt Sn`
b. `Ge gt Sn gt Pb`
c. `Pb gt Ge gt Sn`
d. `Pb gt Sn gt Ge`

Options

A. `Ge gt Pb gt Sn`
B. `Ge gt Sn gt Pb`
C. `Pb gt Ge gt Sn`
D. `Pb gt Sn gt Ge`

Explanation

To solve the question regarding the oxidizing power of tetravalent species in group 14 of the periodic table, we will analyze the elements and their oxidation states step by step.

### Step 1: Identify the Elements in Group 14
Group 14 of the periodic table consists of the following elements:
- Carbon (C)
- Silicon (Si)
- Germanium (Ge)
- Tin (Sn)
- Lead (Pb)

For this question, we will focus on the tetravalent species, which are Ge, Sn, and Pb.

### Step 2: Understand Oxidizing Power
The oxidizing power of a species is determined by its ability to gain electrons (get reduced). A stronger oxidizing agent will more readily accept electrons and thus be reduced more easily.

### Step 3: Analyze the Reduction Reactions
We will look at the reduction of the tetravalent species (Ge⁴⁺, Sn⁴⁺, Pb⁴⁺) to their respective divalent states (Ge²⁺, Sn²⁺, Pb²⁺):
- Ge⁴⁺ + 2e⁻ → Ge²⁺
- Sn⁴⁺ + 2e⁻ → Sn²⁺
- Pb⁴⁺ + 2e⁻ → Pb²⁺

### Step 4: Stability of the Reduced Forms
The stability of the reduced forms (Ge²⁺, Sn²⁺, Pb²⁺) is crucial:
- Ge²⁺ is less stable than Sn²⁺.
- Sn²⁺ is less stable than Pb²⁺.

This trend indicates that as we move down the group, the lower oxidation states become more stable due to the inert pair effect, which is the tendency of the s-electrons to remain non-bonding.

### Step 5: Determine the Order of Oxidizing Power
Since the stability of the reduced forms is inversely related to their oxidizing power:
- Pb⁴⁺ is the easiest to reduce to Pb²⁺ (most oxidizing).
- Sn⁴⁺ is less easy to reduce to Sn²⁺ (moderately oxidizing).
- Ge⁴⁺ is the hardest to reduce to Ge²⁺ (least oxidizing).

Thus, the order of oxidizing power in decreasing order is:
**Pb > Sn > Ge**

### Step 6: Select the Correct Option
From the options given:
a. Ge > Pb > Sn
b. Ge > Sn > Pb
c. Pb > Ge > Sn
d. Pb > Sn > Ge

The correct answer is **d. Pb > Sn > Ge**.

### Summary of Steps
1. Identify the elements in Group 14.
2. Understand the concept of oxidizing power.
3. Analyze the reduction reactions for Ge, Sn, and Pb.
4. Assess the stability of the reduced forms.
5. Determine the order of oxidizing power based on stability.
6. Select the correct option based on the analysis.