Answer the case-based question given below.
Anita stored a white solid substance in a closed container. When she added a few drops of water to this substance, it reacted vigorously and released a large amount of heat. Gradually, it was converted into a soft white powder which is widely used in construction work.
i. Identify the type of chemical reaction.
ii. Name the starting substance mentioned in the passage.
iii. Write the balanced chemical equation for the reaction.