Question

For a reaction to be spontaneous at all temperatures:
A. Only $\Delta H$ would be negative
B. Only $\Delta G$ would be negative
C. $\Delta H$ and $\Delta G$ should be positive
D. $\Delta H$ and $\Delta G$ should be negative

Answer 1

Hint- In science, a spontaneous procedure is one that happens without the expansion of outer energy. A spontaneous procedure may occur rapidly or slowly, on the grounds that spontaneity isn't identified with energy or response rate. A great example is the procedure of carbon as a diamond transforming into graphite.

Complete answer:

For a procedure that happens at steady temperature and pressure, spontaneity can be resolved utilizing the change in Gibbs free energy, which is given by:
$\Delta G = \Delta H - T\Delta S$
where the indication of ΔG relies upon the signs of the changes in enthalpy (ΔH) and entropy (ΔS), just as on the absolute temperature (T). The indication of ΔG will change from positive to negative (or the other way around) where-
$\Rightarrow T = \dfrac{{\Delta H}}{{\Delta S}}$
In situations where ΔG is:
Negative: the procedure is unconstrained and may continue the forward way as composed.
Positive: the procedure is non-unconstrained as composed; however, it might continue precipitously the opposite way.
Zero: the procedure is at equilibrium, with no net change occurring after some time. This arrangement of rules can be utilized to decide four particular cases by looking at the signs of the ΔS and ΔH.
When ΔS > 0 and ΔH < 0, the procedure is consistently unconstrained as composed.
When ΔS < 0 and ΔH > 0, the procedure is rarely unconstrained, yet the converse procedure is consistently unconstrained.
When ΔS > 0 and ΔH > 0, the procedure will be unconstrained at high temperatures and non-unconstrained at low temperatures.
When ΔS < 0 and ΔH < 0, the procedure will be unconstrained at low temperatures and non-unconstrained at high temperatures.
For the last two cases, the temperature at which the spontaneity changes will be controlled by the general magnitudes of ΔS and ΔH.
$\Delta H$and $\Delta G$ should be negative.
Hence, option D is the correct option.

Note: Gibbs free energy which is otherwise called Gibbs capacity or Gibbs energy or free enthalpy is a quantity used to measure the maximum amount of work done in a thermodynamic framework when the temperature and pressure are consistent. Gibbs free energy is denoted as G.