SATHEE: The P Block Elements - Result Question 64

The P Block Elements - Result Question 64

####67. Which one of the following orders is correct for the bond dissociation enthalpy of halogen molecules?

[2016]

(a) $I_{2} > B r_{2} > C l_{2} > F_{2}$

(b) $C l_{2} > B r_{2} > F_{2} > I_{2}$

(d) $F_{2} > C l_{2} > B r_{2} > I_{2}$

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Solution:

(b) Bond dissociation enthalpy decreases as the bond distance increases from $F_{2}$ to $I_{2}$ . This is due to increase in the size of the atom, on moving from $F$ to $I$ .

$F - F$ bond dissociation enthalpy is smaller then $C l - C l$ and even smaller than $B r - B r$ . This is because $F$ atom is very small and hence the three lone pairs of electrons on each $F$ atom repel the bond pair holding the $F$ -atoms in $F_{2}$ molecules. The increasing order of bond dissociation enthalphy is

$I_{2} < F_{2} < B r_{2} < C l_{2}$

The P Block Elements - Result Question 64

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The P Block Elements - Result Question 64

Solution:

Engineering Preparation

Medical Preparation

NCERT Books & Solutions

Important Resources

Other Resources

Syllabus

Test Platform

Sample Mock Test

Mentorship

NCERT Exercise Video Solution

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