For each of the following pairs of substances, determine which has the larger molar entropy at 298 k: (a) br₂(l) or (b) cl₂(g) (c) fe(s) or (d) ni(s) (e) c₂h₆(g) or (f) c₂h₄(g) (g) ccl₄(g) or (h) ch₄(g) (i) hgo(s) or (j) mgo(s) (k) nacl(aq) or (l) mgcl₂(aq)

Explanation:

Entropy is defined as the degree of randomness present in a substance. Therefore, more is the irregularity present in a compound more will be its molar entropy.

Hence, decreasing order to molar entropy in state of matter is as follows.

                     Gases > Liquids > Solids

In the first pair, we are given or . Since, molar entropy of liquids is less than the molar entropy of gases.

Hence, will have larger molar entropy as compared to .

In the second pair, we are given Fe(s) or Ni(s). More is the molar mass of a compound more will its molar entropy. Molar mass of Fe is 55.84 g/mol and molar mass of Ni is 58.69 g/mol.

Hence, molar entropy of Ni(s) is more than the molar entropy of Fe(s).

In the third pair, we are given or . As both the given species are gaseous in nature. So, more is the molar mass of specie more will be its molar entropy.

Molar mass of is 30.07 g/mol and molar mass of is 28.05 g/mol. Therefore, molar entropy of is more than the molar entropy of .

In the fourth pair, we are given or . Molar mass of is 153.82 g/mol and molar mass of is 16.04 g/mol.

Therefore, molar entropy of is more than the molar entropy of .

In the fifth pair, we are given HgO(s) or MgO(s). Molar mass of HgO is 216.59 g/mol and molar mass of MgO is 40.30 g/mol.

Hence, molar entropy of HgO(s) is more than the molar entropy of MgO.

In the fifth pair, we are given NaCl(aq) or . Molar mass of NaCl 58.44 g/mol and molar mass of is 95.21 g/mol.

Hence, the molar entropy of is more than the molar entropy of NaCl(aq).

The answer for this is a