Which element is in Group 2, Period 4 of the periodic table?
A. Ca
B. Be
C. Sr
D. Mg
Answer: Option A
Solution (By JKExamLibrary)
Calcium (Ca, Z=20) has configuration 2,8,8,2. 4 shells → Period 4; 2 valence electrons → Group 2. Mg is Group 2, Period 3. Sr is Group 2, Period 5. Be is Group 2, Period 2.
Explanation:
Acidified copper sulfate (CuSO₄) solution is the electrolyte. The iron spoon is the cathode, and a pure copper plate is the anode. Cu²⁺ ions are reduced at the cathode and deposited on the spoon. Fe from spoon does not go into solution because it is cathode.
Explanation:
A negative catalyst (inhibitor) slows down a reaction. Phosphoric acid (or acetamide) retards the decomposition of H₂O₂ by stabilizing it. MnO₂ is a positive catalyst for H₂O₂ decomposition, speeding it up. Platinum catalyzes SO₂ oxidation in contact process. Iron (Fe) catalyzes ammonia synthesis in Haber process. Negative catalysts are often used to prevent undesirable reactions, e.g., antioxidants in food preservation.
Explanation:
CNG (Compressed Natural Gas) is primarily methane (CH₄). LPG is propane and butane. Methane is the lightest hydrocarbon. CNG is a cleaner fuel for vehicles.
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