1. When carbon dioxide is bubble through a clear solution of calcium hydroxide, a milky solution of calcium carbonate will be formed. The balanced chemical equation for the reaction is as follows: CO2 + Ca[OH]2 = CaCO3 + H2O. That is, one mole of carbon dioxide react with one mole of calcium hydroxide to produce one mole each of water and calcium carbonate.
2. An acidic oxide is defined as those compounds of oxygen which react with water to form acids or react with bases to form salts. They are usually oxides of metals or of metals in high oxidation states. In the chemical equation given in answer 1, one can easily see that carbon dioxide is an acidic oxide because it reacts with calcium hydroxide [which is a base] to produce calcium carbonate, which is a salt.
The answer is B as isotopes are different versions of the same chemical element containing the same amount of protons and electrons but different amounts of neutrons.
Magnesium oxide can be very bad for your health, and when we did an experiment with it in class it was white because it was so hot. It is very flammable.
