Chapter 12, Problem 12.1KSP

Interpretation Introduction

Interpretation:

The compound(s) that are more soluble in water has to be predicted from the following options –

Concept Introduction:

Solubility of a substance depends on various factors like – chemical structure of the substance, temperature, pH etc,

Like dissolves like is a Universal rule which states that polar compounds dissolve more in polar solvents and non-polar compounds dissolve more in non-polar compounds.

Dipole moment is the measure of polarity in polar covalent compounds.

Answer to Problem 12.1KSP

Options (a), (d) and (e) are correct answers.

Explanation of Solution

Reason for correct answers:

The compound given in the options (a), (d) and (c) are polar compounds and so they dissolve in water which is a polar solvent.

The compound given in option (a) is methanol.  It is a polar covalent compound as the $\text{O-H}$ bond in it is polar.   Besides, the molecules form hydrogen bonding with water molecules so that it dissolves well in water.

Figure 1

The compound given in option (d) is cis-1,2-dichloroethene.  The $C-Cl$ bond is polar in nature and the two $C-Cl$ bonds are cis to each other.  Hence being a polar compound it dissolves in water, a polar solvent.

The compound given in option (e) is Potassium iodide and it is an ionic compound made of $K^{+}$ions and $I^{-}$ions held together by electrostatic force of attraction.  It dissociates in water completely into individual ions and thus it is more soluble in water.

Reasons for Incorrect answers:

The compounds given in options ( $\text{O-H}$ b) Carbon tetrachloride and (c) cis-1, 2-dichloroethene are non-polar compounds and do they don’t dissolve in water.

Figure 2

Though the $C-Cl$ bond is polar and has polarity, they are positioned opposite to each other due to which their dipole moment becomes zero.

Therefore polarity of the compound gets cancelled.

Figure 3

Conclusion

The compound(s) that are more soluble in water has been predicted from the given options.