When the moisture condenses, this results in the release of energy. The energy causes the air to be warm and results in the rise of air in the upper atmosphere. This process results in the instability in the atmosphere and cumulonimbus clouds are formed. These clouds support lightening during a thunderstorm.
The solution is found by dividing the mass of the BaO, which is 25.8 grams, by the total mass of the solution, which is 212 grams, then multiplying it by 100 to get the percentage: