Question

1. Rank the indicated bonds in order of increasing polarity: ____<____<____

a)H–NH2

(b) H–PH2

(c) H–OH   

2. Rank the following solutes in order of increasing solubility in pentane [CH3(CH2)3CH3]: ____<____<____

(a) butanol (CH3CH2CH2CH2OH) (b) butanal (CH3CH2CH2CHO) (c) potassium bromide   

Can you please explain how you got the answer? Thank you

Answer 1

Order of increasing polarity: B < A < C

The electronegativity difference between O and H is higher compared to electronegativity differance between N and H which is higher than P and H.

Oxygen is more electronegative element than nitrogen.

2)

Order of increasing solubility: A < B < C

Pentane is a non-polar solvent. butanol is a polar solvent among all solvents given.

Polar solvent soluble in polar solvents and insoluble in non-polar solvents.

So solubility of polar butanol is very less in non-polar penatne.