In nature, one common strategy to make thermodynamically unfavorable reactions proceed is to couple them chemically to reactions that are thermodynamically favorable. as long as the overall reaction is thermodynamically favorable, even the unfavorable reaction will proceed.
part a: consider these hypothetical chemical reactions:
a⇌b,δg= 11.9 kj/mol
b⇌c,δg= -26.7 kj/mol
c⇌d,δg= 7.30 kj/mol
what is the free energy, δg, for the overall reaction, a⇌d?

31.3 kJ/mol is the free energy, ΔG, for the overall reaction, A⇌D.

Explanation:

A⇌B, = 11.9 kJ/mol  ...[1]

B⇌C, = -26.7 kJ/mol  ...[2]

C⇌D, = 7.30 kJ/mol  ...[3]

A⇌D, = ?...[4]

[4] = [1] - [2] - [3]  (Using Hess's law)

31.3 kJ/mol is the free energy, ΔG, for the overall reaction, A⇌D.

he uptake of drugs from the intestine is often strongly influenced by diffusion. for example, consider a water-insoluble steroid for treating inflammation that is solubilized in aggregates of detergent molecules, called micelles. these micelles, aggregates of 80 soap molecules, have a molecular weight of 24,000, a diameter of 2.6 nm, and a charge of -27. the positively charge ions (counterions) in this system are na".

the correct answer is b. a strong acid completely dissociates to its ions when dissolved in water. completely dissociates to and ions. a is incorrect because does not fully ionize to and ions and some remain as the compound . c and d are incorrect because, and do not fall into the category of bronsted lowry acids. a bronsted lowry acid is a proton donor and since both molecules do not have a proton to donate they are not bronsted lowry acids. likewise,   if we use the lewis acid definition, they cannot be acids. a lewis acid is an electron pair acceptor. both and have a complete octet so can not accept any electrons which disqualifies them as acids.