The amount of energy required to break a bond is same as the amount of energy released when the same bond is formed. In gaseous state, the energy required for homolytic cleavage of a bond is called Bond Dissociation Energy (BDE) or Bond Strength. BDE is affected by s-character of the bond and the stability of the radicals formed. Shorter bonds are typically stronger bonds. BDEs for some bonds are given below :



Cl $$-$$ Cl (g) $$\to$$ Cl$$_{(g)}^ \bullet $$ + Cl$$_{(g)}^ \bullet $$ $$\Delta$$H$$^\circ$$ = 58 kcal mol^$$-$$1

H₃C $$-$$ Cl (g) $$\to$$ H₃C$$_{(g)}^ \bullet $$ + Cl$$_{(g)}^ \bullet $$ $$\Delta$$H$$^\circ$$ = 85 kcal mol^$$-$$1

H $$-$$ Cl (g) $$\to$$ H$$_{(g)}^ \bullet $$ + Cl$$_{(g)}^ \bullet $$ $$\Delta$$H$$^\circ$$ = 103 kcal mol^$$-$$1

For the following reaction

CH₄(g) + Cl₂(g) $$\buildrel {light} \over \longrightarrow $$ CH₃Cl(g) + HCl (g)

the correct statement is

The reaction of K₃[Fe(CN)₆] with freshly prepared FeSO₄ solution produces a dark blue precipitate called Turnbull's blue. Reaction of K₄[Fe(CN)₆] with the FeSO₄ solution in complete absence of air produces a white precipitate X, which turns blue in air. Mixing the FeSO₄ solution with NaNO₃, followed by a slow addition of concentrated H₂SO₄ through the side of the test tube produces a brown ring.

Precipitate X is

The reaction of K₃[Fe(CN)₆] with freshly prepared FeSO₄ solution produces a dark blue precipitate called Turnbull's blue. Reaction of K₄[Fe(CN)₆] with the FeSO₄ solution in complete absence of air produces a white precipitate X, which turns blue in air. Mixing the FeSO₄ solution with NaNO₃, followed by a slow addition of concentrated H₂SO₄ through the side of the test tube produces a brown ring.

Among the following, the brown ring is due to the formation of

One mole of an ideal gas at 900 K, undergoes two reversible processes, I followed by II, as shown below. If the work done by the gas in the two processes are same, the value of $$\ln {{{V_3}} \over {{V_2}}}$$ is _________.


(U : internal energy, S : entropy, p : pressure, V : volume, R : gas constant)

(Given : molar heat capacity at constant volume, C_V,m of the gas is $${5 \over 2}$$R)