Question

The names of the elements present in quick lime are : 
(i) Ca (ii) H  (iii) O (iv) C

• A. (i), (ii) and (iii)
• B. (i), (iii) and (iv)
• C. (i) and (iii)
• D. (i), (ii), (iii) and (iv)

Hint:

Key common names and formulas to remember:
Quick Lime = Calcium Oxide = {CaO} (Elements: Ca, O)
Slaked Lime = Calcium Hydroxide = \(Ca(OH)_2\) (Elements: Ca, O, H)
Limestone/Chalk = Calcium Carbonate = \(CaCO_3\) (Elements: Ca, C, O) For this question, quick lime is CaO.

Answer 1

The Correct Option is C

Concept: Quick lime is a common chemical compound with a specific chemical formula. Knowing the formula allows us to identify the constituent elements. Step 1: Identify the chemical name and formula of Quick Lime Quick lime is the common name for Calcium Oxide. The chemical formula for Calcium Oxide is CaO. Step 2: Identify the elements from the chemical formula The formula CaO indicates that one molecule of quick lime contains:
One atom of Calcium (symbol: Ca)
One atom of Oxygen (symbol: O) Step 3: Match the elements with the given list The given list of elements is: % Option (i) Ca (Calcium) % Option (ii) H (Hydrogen) % Option (iii) O (Oxygen) % Option (iv) C (Carbon) From our analysis, quick lime (CaO) contains Calcium (Ca) and Oxygen (O). So, elements (i) Ca and (iii) O are present in quick lime. Step 4: Choose the correct option Option (1) (i), (ii) and (iii) includes Hydrogen (H), which is not in CaO. Option (2) (i), (iii) and (iv) includes Carbon (C), which is not in CaO. Option (3) (i) and (iii) correctly lists Calcium (Ca) and Oxygen (O). Option (4) (i), (ii), (iii) and (iv) includes Hydrogen (H) and Carbon (C), which are not in CaO. Therefore, the elements present in quick lime are Calcium (Ca) and Oxygen (O).