Q 1 :

Given below are two statements:

Statement I: The correct order of first ionization enthalpy values of Li, Na, F and Cl is Na < Li < Cl < F.

Statement II: The correct order of negative electron gain enthalpy values of Li, Na, F and Cl is Na < Li < F < CI

In the light of the above statements, choose the correct answer from the options given below :                [2024]

• Both Statement I and Statement II are true

   

• Both Statement I and Statement II are false

   

• Statement I is true but Statement II is false

   

• Statement I is false but Statement II is true

   

Q 2 :

The electron affinity value are negative for

A.    $\mathrm{Be}\to {\mathrm{Be}}^{-}$

B.    $\mathrm{N}\to {\mathrm{N}}^{-}$

C.    $\mathrm{O}\to {\mathrm{O}}^{2-}$

D.    $\mathrm{Na}\to {\mathrm{Na}}^{-}$

E.    $\mathrm{Al}\to {\mathrm{Al}}^{-}$

Choose the most appropriate answer from the options given below:              [2024]

• A, B and C only

   

• D and E only

   

• A and D only

   

• A, B, D and E only

   

Q 3 :

Given below are two statements :

Statement (I): The oxidation state of an element in a particular compound is the charge acquired by its atom on the basis of electron gain enthalpy consideration from other atoms in the molecule.

Statement (II): $p\pi -p\pi$ bond formation is more prevalent in second period elements over other periods.

In the light of the above statements, choose the most appropriate answer from the options given below:              [2024]

• Both Statement I and Statement II are incorrect

   

• Both Statement I and Statement II are correct

   

• Statement I is incorrect but Statement II is correct

   

• Statement I is correct but Statement II is incorrect

   

Q 4 :

Given below are two statements:

Statement I: Fluorine has most negative electron gain enthalpy in its group.
Statement II: Oxygen has least negative electron gain enthalpy in its group.

In the light of the above statements, choose the most appropriate from the options given below.         [2024]

• Statement I is false but Statement II is true

   

• Both Statement I and Statement II are true

   

• Both Statement I and Statement II are false

   

• Statement I is true but Statement II is false

   

Q 5 :

Given below are two statements:

Statement I: The radii of isoelectronic species increases in the order.  ${\mathrm{Mg}}^{2+}<{\mathrm{Na}}^{+}<{\mathrm{F}}^{-}<{\mathrm{O}}^{2-}$

Statement II: The magnitude of electron gain enthalpy of halogen decreases in the order. $\mathrm{Cl}>\mathrm{F}>\mathrm{Br}>\mathrm{I}$

In the light of the above statements, choose the most appropriate answer from the options given below:        [2025]

• Both Statement I and Statement II are incorrect

   

• Statement I is correct but Statement II is incorrect

   

• Statement I is incorrect but Statement II is correct

   

• Both Statement I and Statement II are correct

   

Q 6 :

For electron gain enthalpies of the elements denoted as ${\Delta }_{\mathrm{eg}}H$, the incorrect option is:           [2023]

• ${\Delta }_{\mathrm{eg}}H\left(\mathrm{Cl}\right)<{\Delta }_{\mathrm{eg}}H\left(\mathrm{F}\right)$

   

• ${\Delta }_{\mathrm{eg}}H\left(\mathrm{I}\right)<{\Delta }_{\mathrm{eg}}H\left(\mathrm{At}\right)$

   

• ${\Delta }_{\mathrm{eg}}H\left(\mathrm{Te}\right)<{\Delta }_{\mathrm{eg}}H\left(\mathrm{Po}\right)$

   

• ${\Delta }_{\mathrm{eg}}H\left(\mathrm{Se}\right)<{\Delta }_{\mathrm{eg}}H\left(\mathrm{S}\right)$

   

Q 7 :

The difference between electron gain enthalpies will be maximum between:           [2023]

• Ar and Cl

   

• Ne and Cl

   

• Ne and F

   

• Ar and F

   

Q 8 :

Given below are two statements:

Statement I: The increasing order of boiling point of hydrogen halides is HCl < HBr < HI < HF.

Statement II: The increasing order of melting point of hydrogen halides is HCl < HBr < HF < HI.

In the light of the above statements, choose the correct answer from the options given below:  [2026]

• Both Statement I and Statement II are true

   

• Statement I is false but Statement II is true

   

• Statement I is true but Statement II is false

   

• Both Statement I and Statement II are false

   

Q 9 :

Given below are two statements :

Statement I : C < O < N < F is the correct order in terms of first ionization enthalpy values.

Statement II : S > Se > Te > Po > O is the correct order in terms of the magnitude of electron gain enthalpy values.

In the light of the above statements, choose the correct answer from the options given below :              [2026]

• Both Statement I and Statement II are false

   

• Both Statement I and Statement II are true

   

• Statement I is false but Statement II is true

   

• Statement I is true but Statement II is false

   

Q 10 :

If the enthalpy of sublimation of Li is 155 kJ ${\mathrm{mol}}^{-1},$ enthalpy of dissociation of ${\mathrm{F}}_2$ is ${\text{150 kJ mol}}^{-1}$, ionization enthalpy of Li is ${\text{520 kJ mol}}^{-1},$ electron gain enthalpy of F is ${\text{−313 kJ mol}}^{-1},$ standard enthalpy of formation of LiF is ${\text{−594 kJ mol}}^{-1}.$The magnitude of lattice enthalpy of LiF is __________ ${\text{kJ mol}}^{-1}.$(Nearest Integer)  [2026]

Q 11 :

Correct electron gain enthalpy order is

• Ne > S > F > Cl

   

• He > Ne > Ar = Kr > Xe

   

• O > S > Ne > He

   

• Ne > S > Cl > F

   

Q 12 :

The formation of the oxide ion $O^{2-}\left(g\right)$, from oxygen atom requires first an exothermic and then an endothermic step as shown below:

$O_{\left(g\right)}+e^{-}\to {O^{-}}_{\left(g\right)};{\Delta }_{1}H°=-141kJmo{l}^{-1}$

${O^{-}}_{\left(g\right)}+e^{-}\to {O^{2-}}_{\left(g\right)},{\Delta }_{2}H°=+780kJmo{l}^{-1}$

Thus process of formation of $O^{2-}$ in gas phase is unfavourable even though $O^{2-}$ is isoelectronic with neon. It is due to the fact that

• electron repulsion out weighs the stability gained by achieving noble gas configuration

   

• $O^{-}$ ion has comparatively smaller size than oxygen atom

   

• Oxygen is more electronegative

   

• Addition of electron in oxygen results in larger size of the ion.