Question

Which correctly lists the following in order of increasing entropy? i. 1 mol of HCl (g) at 50 ° C ii. 1 mol of NaCl (s) at 25 ° C iii. 2 mol of HCl (g) at 50 ° C iv. 1 mol of HCl (g) at 25 ° C View Available Hint(s)

Answer 1

Answer: 1 mol of NaCl(s) at
`25^0C`< 1 mol of HCl(g) at
`25^0C` < 1 mol of HCl(g) at
`50^0C` < 2 mol of HCl(g) at
`50^0C`

Step-by-step explanation:

Entropy is the measure of randomness or disorder of a system. If a system moves from an ordered arrangement to a disordered arrangement, the entropy is said to decrease and vice versa.

More number of moles has more randomness and thus has higher entropy. As gaseous form has more randomness and thus has more entropy than solid form. Higher temperature leads to increase in kinetic energy and thus randomness increases and has higher entropy.

Thus the increasing order of entropy is : 1 mol of NaCl(s) at
`25^0C`< 1 mol of HCl(g) at
`25^0C` < 1 mol of HCl(g) at
`50^0C` < 2 mol of HCl(g) at
`50^0C`

Answer 2

so, the order of increasing entropy is

iii>i>iv>ii

Step-by-step explanation:

Entropy of Gases id higher than that of liquids is higher than that of solids. And with increase in temperature of system its entropy also increases. So, these two observations we can conclude that

i) 1 mol of HCl (g) at 50 ° C : it is gas at high temperature as compared to HCl gas at lower temperature.

ii) 1 mol of NaCl (s) at 25 ° C : this is solid so will have lower entropy than gas.

iii) 2 mol of HCl (g) at 50 ° C: the moles are more so will have more entropy than 1 mol of HCl (g) at 50 ° C

iv) 1 mol of HCl (g) at 25 ° C : will have lower entropy than HCl gas at higher temperature but will have higher entropy than solid Nacl.

so, the order of increasing entropy is

iii>i>iv>ii