Question 51 OSV02 - Mate - Offshore Supply Vessels

The Correct Answer is A **Explanation of Option A (Toluene):** Toluene $\left(\mathrm{C}_{6} \mathrm{H}_{5} \mathrm{CH}_{3}\right)$ is a highly flammable liquid with a low flash point $\left(4^{\circ} \mathrm{C}\right)$. When exposed to flame or high heat, Toluene vaporizes rapidly and forms a flammable mixture with air. If this mixture ignites in an enclosed or semi-enclosed space, it can cause a rapid, violent combustion, leading to an explosion hazard. It is classified as an extremely hazardous substance due to its high flammability and potential for fire/explosion. **Explanation of Incorrect Options:** * **B) Formic acid:** Formic acid $(\mathrm{HCOOH})$ is combustible, meaning it can burn, but it has a relatively high flash point $\left(69^{\circ} \mathrm{C}\right)$ and is not considered a highly volatile or reactive substance that typically poses an explosion hazard solely upon exposure to an open flame under normal conditions. It is corrosive but less prone to explosion than highly volatile solvents like toluene. * **C) Nitrous oxide:** Nitrous oxide $\left(\mathrm{N}_{2} \mathrm{O}\right)$ is an oxidizing gas (it supports combustion) and is non-flammable itself. While it can intensify a fire, it does not act as the fuel source and does not explode on its own when exposed to flame. However, compressed gas cylinders containing nitrous oxide can rupture explosively if heated due to pressure buildup, but the gas itself is not the explosion hazard in the same manner as a highly flammable liquid/vapor mixture. * **D) Tallow:** Tallow is rendered animal fat. It is a solid or semi-solid at room temperature and is combustible (it will burn) but has a very high flash point and low volatility. It does not readily vaporize to form an explosive mixture with air when exposed to a flame, making it a fire risk, but not typically an explosion hazard.