Question

Which of the following is known as 'Slaked Lime'?

• A. Calcium Oxide
• B. Calcium Carbonate
• C. Calcium Hydroxide
• D. Sodium Hydroxide

Hint:

Remember the clear distinctions between these three calcium compounds:
- \(CaO\) = Quicklime
- \(Ca(OH)_2\) = Slaked lime
- \(CaCO_3\) = Limestone

Answer 1

The Correct Option is C

Step 1: Understanding the Question:
The question asks for the common name of the chemical compound calcium hydroxide.

Step 2: Key Formula or Approach:
Associate common industrial and household names with their systematic chemical formulas for calcium compounds.

Step 3: Detailed Explanation:

• Let us define the common names of the calcium compounds listed:
- (A) Calcium Oxide (\(CaO\)): Commonly known as quicklime or burnt lime. It is produced by heating limestone in a kiln.
- (B) Calcium Carbonate (\(CaCO_3\)): Commonly occurs in nature as limestone, marble, chalk, and seashells.
- (C) Calcium Hydroxide (\(Ca(OH)_2\)): Commonly known as slaked lime. It is prepared by adding water to quicklime (calcium oxide) in an exothermic reaction:
\[ CaO\text{(s)} + H_2O\text{(l)} \to Ca(OH)_2\text{(s)} + \text{Heat} \] - A clear saturated aqueous solution of calcium hydroxide is called lime water.
- A suspension of slaked lime in water is called milk of lime, which is used for whitewashing.

• Therefore, calcium hydroxide is known as slaked lime.


Step 4: Final Answer:
Calcium Hydroxide is known as slaked lime.