Question

For each of the following pairs of compounds, identify the one that is more likely to be soluble in water.

(a) Br₂ or NaBr

(b) CH₃CH₂OH or CH₃OCH₃

(c) CO₂ or KOH

(if you dont mind explaining so I can understand this, it would be great - Thanks in advance)

Answer 1

The interactions between the solute and solvent makes the solute to dissolve in the solvent. More are the attractive interactions between them, more is the solubility.

It is also believed that like dissoves like i.e. a polar molecule tend to solublize more in polar solvents.

Water is a polar solvent.

a) Br2 is a non polar molecule, while NaBr is an ionic salt and thus dissociates into Na+ and Br- ions into water. NaBr has ionic interactions with water which makes it soluble in it.

Ans: NaBr

b) CH3CH2OH is an alcohol molecule which is capable of strong hydrogen bonding with water molecules while ether molecule has poor or no hydrogen bonding ability to water molecules. Thus, CH3CH2OH is more soluble.

Ans : CH3CH2OH

c) Same reason as eplained for part a) CO2 is a non polar molecule, while KOH dissociates into K+ and OH- ions capable of strong ionic interactions with water.

Ans: KOH