Question 66

The Correct Answer is C ### Explanation for Option C (Correct) A Grade B flammable liquid is defined as a liquid with a flash point below $-4{ }^{\circ} \mathrm{C}$ but above $-20{ }^{\circ} \mathrm{C}$. Chlorallylene (specifically, 3-chloro-1-propene or allyl chloride) has a flash point of approximately $-18{ }^{\circ} \mathrm{C}$ (or $-20{ }^{\circ} \mathrm{C}$, depending on the specific source, often hovering right around the Grade B cutoff). This value places it squarely within the Grade B classification range ($-4{ }^{\circ} \mathrm{C} >$ Flash Point $> -20{ }^{\circ} \mathrm{C}$). ### Why Other Options Are Incorrect **A) Allyl alcohol:** Allyl alcohol (Prop-2-en-1-ol) has a flash point of approximately $21{ }^{\circ} \mathrm{C}$. Because its flash point is above $-4{ }^{\circ} \mathrm{C}$ but below $21{ }^{\circ} \mathrm{C}$ (or $23{ }^{\circ} \mathrm{C}$ depending on the grading system), it is typically classified as a **Grade C** flammable liquid (or sometimes Class IB/IC depending on the specific standard used, but it does not meet the criteria for Grade B). **B) Paraldehyde:** Paraldehyde (2,4,6-trimethyl-1,3,5-trioxane) has a flash point of approximately $18{ }^{\circ} \mathrm{C}$ to $27{ }^{\circ} \mathrm{C}$. This places it in the **Grade C** category. **D) Ethylene oxide:** Ethylene oxide is an extremely volatile chemical that exists as a gas at room temperature, although it is stored and handled as a refrigerated liquid. Its flash point is extremely low, around $-30{ }^{\circ} \mathrm{C}$. This low flash point places it in the **Grade A** category (flash point below $-20{ }^{\circ} \mathrm{C}$), making it much more flammable than a Grade B liquid.