Under what soil condition do you think a farmer would treat the soil of his fields with quick lime (calcium oxide) or slaked lime (calcium hydroxide) or chalk (calcium carbonate)?
A farmer would treat the soil with quick lime (calcium oxide), slaked lime (calcium hydroxide), or chalk (calcium carbonate) when the soil becomes acidic or has a high concentration of H⁺ ions.
All these substances are basic in nature. As indicated in the context, basic substances can be used to neutralize acids. When the soil is too acidic, it becomes harmful for crop growth. By adding these basic calcium compounds, the farmer can neutralize the excess acid present in the soil. This helps restore the soil's pH balance, making it suitable for healthy cultivation of crops.
Explanation
This question tests the student's understanding of acid-base neutralization in a real-life application. The context mentions that sodium hydrogencarbonate is 'a mild non-corrosive basic salt' and asks students to correlate why it can be used to neutralize an acid. Similarly, quick lime, slaked lime, and chalk are all basic compounds containing calcium. The context also shows that chalk (calcium carbonate) is a form of calcium carbonate. When soil becomes acidic (high H⁺ ion concentration), these basic substances are added to neutralize the acidity and restore soil health.