Question

The amount of heat to be withdrawn from 3 kg of water at \(0^{\circ}C\) to obtain 3 kg of ice at \(0^{\circ}C\) in an icemaker is (latent heat of fusion of ice is \(80 \text{ kcal/kg}\))

• A. \(400 \text{ kcal}\)
• B. \(160 \text{ kcal}\)
• C. \(320 \text{ kcal}\)
• D. \(80 \text{ kcal}\)
• E. \(240 \text{ kcal}\)

Hint:

Latent heat of fusion of ice = \(80 \text{ kcal/kg} = 336 \text{ kJ/kg}\).

Answer 1

Answer: (E)

Step 1: Understanding the Concept:
Heat to be withdrawn = heat released during freezing = \(m \times L_f\).

Step 2: Detailed Explanation:
\(Q = m \times L_f = 3 \text{ kg} \times 80 \text{ kcal/kg} = 240 \text{ kcal}\)

Step 3: Final Answer:
\(240 \text{ kcal}\) must be withdrawn.