Answer:
Step-by-step explanation:
The correct answer is B. ΔSfº is not equal to zero for any of these substances because perfectly crystalline solids do not exist and absolute zero cannot be achieved.
The standard entropy of formation (ΔSfº) is a measure of the change in entropy that occurs when one mole of a substance is formed from its elements in their standard states. In order to have a standard entropy of formation equal to zero, the substance would need to have no change in entropy during its formation.
Option B states that ΔSfº is not equal to zero for any of the substances listed because perfectly crystalline solids do not exist and absolute zero cannot be achieved. This is a correct statement because the formation of any substance will involve some degree of change in entropy, even if it is extremely small.
The other options, A, C, D, and E, suggest specific substances for which the standard entropy of formation may or may not be zero. However, these options are not correct because the formation of any substance will involve some change in entropy.
It is important to understand that the concept of standard entropy of formation involves the change in entropy and is not typically equal to zero for any substance.