Typically, the actual yield is lower than the theoretical yield because few reactions complete (i.e., are not 100% efficient) or because not all of the product in a reaction is collected. It is also conceivable for the real yield to exceed the theoretical yield.
What is theoretical yield ?
Theoretical yield is what would be obtained if 100% of the reaction was completed and no product was wasted in any way; however, procedures are not this efficient. Everything is dependent on the experimenter's precision and the reaction. Some reactions are reversible, meaning that less than 100% of the reaction proceeds to completion; some reactions do not go to completion because they require a large amount of energy or additional time, for example. Substances in the reaction may be lost throughout the method or difficult to separate from other sections of the experiment. In chemistry, some degree of inaccuracy is always expected.
It is a covalent bond. Whenever a compound uses such suffixes like mono, di, tri, tetra, and so on, it is a covalent compound- thus having covalent bonds.
