In tropical and Indian geography, laterite soils are characterized by particularly high amounts of which chemical compound?

Introduction / Context:
Laterite soils are common in tropical regions with high rainfall and temperature, including parts of India. Exam questions often test the characteristic composition and appearance of laterite soil, which is important in agriculture and geography.

Given Data / Assumptions:
- The question asks specifically what laterite soils contain in high amounts.
- The options list different compounds such as calcium carbonate, silicates, calcites, and iron oxide.
- We assume standard textbook descriptions of laterite soil.

Concept / Approach:
Laterite soils form under conditions of intense weathering and leaching in hot, humid climates. Silica and many bases are leached away, leaving behind oxides and hydroxides of iron and aluminum. Because of this high iron oxide content, laterite soils often appear red, brown, or yellowish. They are sometimes used as building material when hardened, and are generally poor in nitrogen, potassium, and organic matter.

Step-by-Step Solution:
Step 1: Recall that laterite soil is typically red or reddish-brown. Step 2: Understand that this colour is due to the presence of iron oxides. Step 3: Know that in highly leached soils, many soluble compounds are carried away by rain, leaving iron and aluminum oxides. Step 4: Compare this with the answer choices and identify the one that mentions iron oxide specifically. Step 5: Choose iron oxide as the correct characteristic component.

Verification / Alternative check:
Geography textbooks and soil science references describe laterite soil as rich in iron and aluminum oxides, especially iron oxides that give the soil its distinctive colour. Diagrams and photographs of laterite soil in India often show a red surface, confirming the high iron content.

Why Other Options Are Wrong:
Option A: Calcium carbonate is more characteristic of calcareous soils and desert soils, not laterite soils formed under heavy rainfall and leaching.
Option B: Silicates such as quartz and feldspar are widespread in many rocks and soils, but laterite soils are defined by what remains after extensive leaching, especially iron and aluminum, rather than silicates.
Option C: Calcites may accumulate in arid and semi-arid soils, but laterite soils are associated with high rainfall regions and intense chemical weathering, not calcite accumulation.

Common Pitfalls:
Students sometimes mix up the characteristics of different soil types, especially red soil, black soil, and laterite soil. A helpful memory trick is to associate laterite with “lateritic red blocks” and iron, while black soil is linked with clay and cotton cultivation, and alluvial soil with river deposits.

Final Answer:
The correct answer is iron oxide, often giving the soil a reddish colour because laterite soils are distinguished by high iron oxide content remaining after intense leaching in tropical climates.