The empirical formula is obtained when we divide the molecular formula with a whole number giving the simplest ratio of all the elements (in whole number).
a) C₁₂H₂₂O₁₁ :
There is no number with which we can divide the ratio further to get a simpler formula hence the molecular formula of the given compound is the empirical formula of the compound. Hence it is correct.
(C₁₂H₂₂O₁₁),
(b) C₈H₁₂O₄
The empirical formula can be obtained by dividing the formula with "4"
Well, one is if heat is absorbed by the system from the surroundings, the system gains heat from the surroundings and so the temperature of the surroundings decreases.