The correct order in which the O-O bond

length increases in the following is

1. H₂O₂<O₂<O₃

2. O₃<H₂O₂<O₂

3. O₂<O₃<H₂O₂

4. O₂<H₂O₂<O₃

The incorrect match among the following is:

1. B < C < N < O (increasing first ionisation enthalpy)

2. I < Br < F < Cl (increasing electron gain enthalpy)

3. Li < Na < K < Rb (increasing metallic radius)

4. Al³⁺ < Mg²⁺ < Na⁺ <F^- (increasing ionic size)

The correct sequence of increasing radii is - 

The formation of the oxide ion O^2-(g), from oxygen atom requires first an exothermic and

then an endothermic step as shown below,

$\mathrm{O}\left(\mathrm{g}\right) + \mathrm{e}- \stackrel{ }{\to } {\mathrm{O}}^{-}\left(\mathrm{g}\right); {∆}_{\mathrm{f}}\mathrm{H}° = -141{\mathrm{kJmol}}^{-1}$
${\mathrm{O}}^{-}\left(\mathrm{g}\right) +\hspace{0.17em}{\mathrm{e}}^{-} \stackrel{ }{\to }{\mathrm{O}}^{2-}\left(\mathrm{g}\right); {∆}_{\mathrm{f}}\mathrm{H}° = +780 \mathrm{kJ} {\mathrm{mol}}^{-1}$

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

1. electron repulsion outweighs the stability gained by achieving noble gas configuration

2. O^- ion has comparatively smaller size than oxygen atom

3. Oxygen is more electronegative

4. addition of electron in oxygen result in large size of the ion

Be²⁺ is isoelectronic with which of the following ions?

1. H⁺

2. Li⁺

3. Na⁺

4. Mg²⁺

The correct order of the decreasing ionic radii among the following isoelectronic species is : 

1. Ca²⁺ > K⁺ > S^2- > Cl^-

2. Cl^- > S^2- > Ca²⁺ > K⁺

3. S^2- > Cl^- > K⁺ > Ca²⁺

4. K⁺ > Ca²⁺ > Cl^- > S^2-

The correct order of increasing electron gain enthalpy with a negative sign for the elements O, S, F, and Cl is : 

1. Cl < F < S < O                   

2. O < S < F < Cl

3. F < S < O < Cl                   

4. S < O < Cl < F

Which one of the following compounds is a peroxide ?

1. KO₂

2. BaO₂

3. MnO₂

4. NO₂

The sequence of ionic mobility in aqueous solution is

1. K⁺>Na⁺>Rb⁺>Cs⁺

2. Cs⁺>Rb⁺>K⁺>Na⁺

3. Rb⁺>K⁺>Cs⁺>Na⁺

4. Na⁺>K⁺>Rb⁺>Cs⁺

Which one of the following arrangements does not give the correct picture of the trends indicated against it?

(1) F₂ > Cl₂ > Br₂ > I₂ :Oxidising power

(2) F₂ < Cl₂ > Br₂ > I₂ : Electron gain enthalpy

(3) F₂ > Cl₂ > Br₂ > I₂ : Bond dissociation energy

(4) F₂ > Cl₂ > Br₂ > I₂: Electronegativity