Answer:
Methyl orange is an indicator which turns yellow in an alkaline solution.
I'm not writing random things to reach the 20 character requirement so I can tell you that Magnesium has the least amount of atoms.
2HCO3 - + Ca2+ CaCO3 + CO2 + H2O Bicarbonate (HCO3-) combines with calcium ions in the water to make calcium carbonate (CaCO3, limestone). This process can occur both within organisms such as corals or as a simple chemical reaction in the water itself.
