Of the following reactions occurring at 25ºc, which one involves the greatest increase in entropy? h2(g) + cl2(g) = 2 hcl(g)h2o(s) = h2o(l)pb2+(aq) + 2 cl-(aq) = pbcl2(s)co2(s) = co2(g)

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.

is positive when randomness increases and is negative when randomness decreases.

a)

2 molesof gas are converting to 2 moles of another gas , thus is zero.

b)

1 mole of solid is converting to 1 mole of liquid, the randomness increases and thus is positive.

b)

2 moles of ions are converting to 1 mole of solid, the randomness decreases and thus is negative

d)

1 mole of solid is converting to 1 mole of gas, the randomness increases drastically and thus is highly positive.

the best answer is d because the strong cohesion is caused by the ability of water molecules to undergo hydrogen bonding.

a is incorrect because when water solidifies, it becomes   ice, which expands and occupies a bigger volume for the same mass of water in its liquid state.

b is incorrect because water has high surface tension. besides bonding to itself it hydrogen bonds to other molecules at the top decreasing possibility for breaking of attractive forces.

c is incorrect because the water molecule has oxygen which is highly electronegative and so pulls the electron pair towards itself creating a dipole moment, making the molecule polar.

e is incorrect because water has strong adhesion, ability to stick to other molecules such as glass because of this molecules having stronger hydrogen bonding than water.