For the of freezing liquid ethanol at a given temperature and pressure, a. δh is positive and δs is positive. b. δh is positive and δs is negative. c. δh is negative and δs is positive. d. δh is negative and δs is negative.

ΔH is negative and ΔS is negative.

Explanation:

Endothermic reaction -

The type of reaction in which energy is absorbed in the form of heat is known as endothermic reaction .

The reaction mixture usually get cooled after the reaction .( temperature decreases ) .

The sign of ΔH of an Endothermic  reaction is positive .

For the of process of freezing the liquid ethanol  ,  energy in the form of heat is released and hence , exothermic reaction ΔH is negative  .

In the process of freezing , liquid is converted to solid , i.e. , the randomness reduces , and hence , entropy also decreases , hence , ΔS is negative .

c. heat could easily travel through the molecules in the air and escape/enter the flask. removing the air slows down the heat transfer.