Question

For a temperature higher than $274K$, which of the following process is correct?

• A. $H_{2}O\left(s\right)\to H_{2}O\left(l\right)$ is exothermic and spontaneous
• B. $H_{2}O\left(l\right)\to H_{2}O\left(s\right)$ is endothermic and spontaneous
• C. $H_{2}O\left(g\right)\to H_{2}O\left(l\right)$ is endothermic and spontaneous
• D. $H_{2}O\left(s\right)\to H_{2}O\left(l\right)$ endothermic and spontaneous
• E. $H_{2}O\left(l\right)\to H_{2}O\left(s\right)$ is exothermic and spontaneous

Answer 1

Answer: (D)

$H_{2}O\left(s\right)\to H_{2}O\left(l\right)$ endothermic and spontaneous

The temperature $274K$ corresponds to $1^{o}C$.
The melting point of ice is $273K$ or $0^{o}C$.
For a temperature higher than $274K$, water would not exist in solid form. The ice will melt to form liquid water.
Nature tends to become more disordered or random.
Entropy of a $H_{2}O\left(l\right)$ system is higher than the entropy of a $H_{2}O\left(s\right)$ system. Thus during melting of ice, the entropy of system increases $(\Delta S>0)$. Also, melting of ice is due to absorption of heat. The heat enters system, leaves surroundings, The process is Endothermic and is spontaneous. At higher temperature $(T\Delta S>\Delta H)$ so $\Delta G=\Delta H-T\Delta S<0$