A solution turns phenolphthalein pink. Which of the following could it be? MCQ with Answer and Explanation

Explanation:
Limestone is CaCO₃. On strong heating, it decomposes to calcium oxide (quicklime) and carbon dioxide: CaCO₃ → CaO + CO₂. This is a decomposition reaction used in cement and lime manufacturing. CaO is used in building and as a drying agent.

Explanation:
CO₂ is the primary anthropogenic greenhouse gas from fossil fuel combustion. N₂, O₂ not IR active. Ammonia is not a major GHG. Methane, N₂O also contribute.

Explanation:
Ernest Rutherford, in 1911, along with Geiger and Marsden, bombarded a thin gold foil with alpha particles. Most passed through, some were deflected at large angles, leading to the nuclear model of the atom—a small, dense, positively charged nucleus with electrons around it. Thomson's plum pudding model predicted no large deflections. Chadwick discovered neutron.