Question

Arrange the following in the order of property indicated for each set:Arrange the following in the order of property indicated for each set:

(i) H2O, NH3, HCl, H2 (increasing magnitude of intermolecular forces)​

Answer 1

Answer:

(i) I

2

<F

2

<Br

2

<Cl

2

The electron affinity of Chlorine is maximum in the periodic table and so the bond dissociation enthalpy. Flourine has lower bond dissociation enthalpy than Br

2

and Cl

2

. Due to small size electronic repulsion is very high. I

2

has lowest bond dissociation enthalpy due to quite larger size it is easiest to break the bond.

(ii) HF<HCl<HBr<HI⇒Acidic strength of Halogen acids increases down the group.

(iii) BiH

3

<SbH

3

<AsH

3

<PH

3

<NH

3

⇒ Basic strength decreases down the group because as we go down the group the size of the atom and thus the electron density decreases. These compounds are lewis base having 1 lone pair on the central atoms. As the electron density decrease the tendency to donate electron pair decreases.