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

Answer 1

Answer:

The order of increasing entropy will be:

1 mol of NaCl (s) at 25 ° C < 1 mol of HCl (g) at 25 ° C<  1 mol of HCl (g) at 50 ° C < 2 mol of HCl (g) at 50 ° C

Explanation:

The entropy increases with

a) increase in temperature

b) state of matter (the entropy order of matter is gas > liquid > solid)

So here

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.