Respiratory failure .Mosquito larvae need to breathe air. They do this through their tails, which they push through the surface of the water they live in. The water tension keeps their air-holes open above the surface.

Kerosene is less dense than water and has much lower surface tension. The mosquito larva pushes it's tail up into the air, then sinks down through the kerosene layer. That means it cannot breathe. So the mosquito larvae die.

**Respiratory Failure**

Kerosene and petrol are both hydrocarbon-based substances that have the ability to spread over the water surface due to their low density. When these substances are spread over the water surface where mosquito larvae reside, they can have detrimental effects on their survival. One of the main reasons for the death of mosquito larvae when exposed to kerosene or petrol is respiratory failure.

**1. Mosquito Larvae and Respiration**

Mosquito larvae are aquatic insects that live in water bodies such as ponds, lakes, and stagnant water. They have specialized structures called spiracles, which are small tubes located on their abdomen. These spiracles serve as respiratory openings through which the larvae obtain oxygen from the surrounding water. Oxygen is essential for the larvae's survival as it is necessary for various physiological functions, including metabolism and energy production.

**2. Effect of Kerosene and Petrol**

When kerosene or petrol is spread over the water surface, they form a thin layer that covers the air-water interface. This layer acts as a barrier, preventing the diffusion of oxygen from the air into the water. As a result, the mosquito larvae are unable to access the vital oxygen they require for respiration.

**3. Oxygen Deprivation and Consequences**

The respiratory failure caused by the presence of kerosene or petrol on the water surface leads to oxygen deprivation for the mosquito larvae. Without sufficient oxygen, the larvae experience a lack of energy production and metabolic dysfunction. This oxygen deprivation ultimately leads to the death of the mosquito larvae.

**4. Other Possible Factors**

While respiratory failure is the primary cause of death for mosquito larvae exposed to kerosene or petrol, other factors may also contribute to their demise. These factors include excretory failure, the inability to take in food, and the inability to molt. However, the main and most immediate cause of death is the respiratory failure resulting from the oxygen deprivation caused by the presence of kerosene or petrol.

In conclusion, when kerosene or petrol is spread over the water surface where mosquito larvae reside, the larvae die primarily due to respiratory failure. The hydrocarbon-based substances form a barrier that prevents the diffusion of oxygen into the water, depriving the larvae of the oxygen necessary for their respiration. This leads to a lack of energy production and metabolic dysfunction, ultimately resulting in the death of the mosquito larvae.