Question

A farmer intends to fumigate the broiler shed of size 500 cu.ft before the arrival of new batch of chicks. What will be the recommended doses of potassium permanganate and formaldehyde for the proper shed disinfection?

• A. 200 g & 200 mL
• B. 300 g & 600 mL
• C. 300 g and 300 mL
• D. 200 g & 400 mL

Hint:

The mixing ratio of Potassium Permanganate to Formalin is always 1:2 by weight-to-volume (e.g., 20 g to 40 mL, or 200 g to 400 mL).
Always add the formalin liquid to the potassium permanganate crystals in a deep container, never the other way around, as the reaction is highly exothermic.

Answer 1

The Correct Option is D

Step 1: Understanding the Concept:
Fumigation is a chemical disinfection method that uses formaldehyde gas generated by reacting formalin (a \(40\%\) solution of formaldehyde) with potassium permanganate (\(KMnO_4\)) to sterilize empty poultry houses.
Key Formula or Approach:
The standard single-strength (1X) fumigation recipe per \(100 \text{ cubic feet (cu.ft)}\) of space is:
- Potassium Permanganate (\(KMnO_4\)) = \(20 \text{ g}\)
- Formalin (\(40\%\) Formaldehyde) = \(40 \text{ mL}\)
For thorough terminal disinfection of poultry sheds prior to the arrival of a new flock, a double-strength (2X) concentration is highly recommended to eliminate resistant pathogens:
- Potassium Permanganate (\(KMnO_4\)) = \(40 \text{ g}\) per \(100 \text{ cu.ft}\)
- Formalin = \(80 \text{ mL}\) per \(100 \text{ cu.ft}\)

Step 2: Detailed Explanation:
The volume of the broiler shed is \(500 \text{ cu.ft}\).
Using the recommended double-strength (2X) fumigation dosage:
- Amount of \(KMnO_4\) required:
\[ \text{Weight} = 40 \text{ g} \times \left( \frac{500}{100} \right) = 40 \text{ g} \times 5 = 200 \text{ g} \] - Amount of Formalin required:
\[ \text{Volume} = 80 \text{ mL} \times \left( \frac{500}{100} \right) = 80 \text{ mL} \times 5 = 400 \text{ mL} \] This matches the dosage given in option (D) (\(200 \text{ g}\) and \(400 \text{ mL}\)).

Step 3: Final Answer:
The recommended dose for fumigating a 500 cu.ft shed is 200 g of potassium permanganate and 400 mL of formaldehyde.