Explanation:

Lattice energy -

It can be defined as the energy required to convert one mole of an ionic solid into gaseous ionic constituents.

Lattice energy is a measure of the strength of the ionic bonds in an ionic compound.

It provides insight into several properties of ionic solids including their volatility, their solubility, and their hardness. The lattice energy of an ionic solid cannot be measured directly.

Generally, this quantity is expressed in terms of kilojoules per mole (kJ/mol).

We know that the lattice energy is directly proportional to the product of the charges of the ions and inversely proportional to the separation between the centres of the ions, i.e., the size of the ions.

Since all the compounds have the same cation, i.e., Li⁺, the size of the anions will be considered.

Down the group, size increases, i.e., F⁻<Cl⁻<Br⁻<I⁻

Thus, the correct order of lattice energy is: LiF > LiCl > LiBr > LiI

Explanation:

All the Xenon Fluorides are strongly oxidizing.

XeF₄ and XeF₆ are expected to oxidize because in both the reactions, XeF₄ and XeF₆ caused oxidation.

⇒ 6 XeF4 + 12 H₂O → 4 Xe + 2 XeO₃ + 24 HF + 3O₂

⇒ XeF6 + 3 H2O → XeO3 + 6 HF

Explanation-

The tendency of an element to lose the electrons to form the positive ions is called the electropositive character.

The elements which have very low ionization energies have a higher tendency to lose electrons and therefore they are electropositive or metallic in their behavior.

If the electronegativity difference increases, ionic character subsequently increases. This increases stability. Dipole moment this way increases the reducing bond length and increases stability.

Stability of the interhalogen compounds will depend on the electropositive character of central atom.

As the electropositive character of the central atom increases, the electronegativity difference increases thus stability increases.

Explanation-

Lone pair electron-It refers to a pair of valence electrons that in a covalent bond are not exchanged with another atom and is often called an unshared pair or non-bonding pair. In the outermost electron shell of atoms, lone pairs are found.

Xenon belongs to the noble gas family and so has eight electrons in its outermost shell. It reacts directly with fluorine under appropriate conditions to form three binary fluoride, which are XeF₂, XeF₄ and XeF₆.

According to VSEPR theory, the total number of electron pairs in a molecule is given by 

Total number of electron pairs = $\frac{l_b+b_p}{2}$

lp = lone pair and b_p = bond pair

Given data and Calculation-

XeF₂-

In the case of XeF_2, there are two Xe−F bonds, also the number of electron pairs are $\frac{8+2}{2}=5$

Out of these two are bond pairs, therefore the number of lone pairs of electrons on Xenon is 3 .

XeF4-

Explanation-

I₂ is a weak oxidizing agent.

I₂ is less reactive than Cl, Br, and F.

KCl → K⁺ + Cl^-

KF → K⁺ + F^-

KBr → K⁺ + Br^-

I₂ can not oxidize Cl^-, Br^-, F^- to Cl₂, Br_2, and F₂ as it is a weak oxidizing agent.

As the reactivity decreases when we move downward in the table, so upper halogen can replace the lower halogen. 

So I₂ can not replace  Cl-, Br-, F-  as it is less reactive.

'So None of the above will be correct.

Explanation-

Bond energy-

Bond Energy, also known as average bond enthalpy or simply bond enthalpy, is a quantity that offers insight into the strength of a chemical bond.

The average value obtained from the bond dissociation enthalpies (in the gaseous phase) of all the chemical bonds of a specific type in a given chemical compound is defined as bond energy.

Therefore, the bond energy of a chemical bond in a given compound can be visualized as the average amount of energy required to break one such chemical bond.

The bond energy of a chemical bond is directly proportional to the stability of that bond. This implies that the greater the bond energy of a given chemical bond between two atoms, the greater the stability of that chemical bond.

The bond energies of Chlorine, Bromine, and Iodine decrease down the group as the size of the atom increases.

The bond energy of Fluorine, is, however, lower than those of Chlorine and Bromine because of interelectronic repulsions present in the small atom of Fluorine.

Bond Energy order is CI₂ > Br₂ > F₂ > I₂.​

Explanation:

⇒ Helium is a light gas, lighter in comparison to air which is mostly nitrogen and oxygen and it is non-inflammable in nature, and hence it is used to fill air balloons. But helium is not lighter than hydrogen gas as its atomic weight is 4 while the molecular weight of hydrogen is 2.

Hence Option 3 is incorrect.

⇒ Helium does not freeze at atmospheric pressure and only at pressures that are 20 times the atmospheric pressure will the helium freeze. Hence, liquid helium, because of its low boiling point, is used in many cryogenic systems when a temperature below the boiling point of nitrogen is needed.

⇒ Liquid helium is used as a coolant for many superconducting windings. It has a boiling point of 4.2K, far below the critical point of most winding materials. Both helium and carbon dioxide are used to cool nuclear reactors.

Note:

Carbon dioxide is used in the gas-cooled nuclear reactors, absorbing the heat from the surrounding elements and reaching 650oC.

Hydrogen gas is 7% more buoyant than helium but helium is preferred over hydrogen due to the fire risks associated with it. But when it comes to weight, helium is heavier in comparison to hydrogen.

Explanation:

XeO₂F₂ Molecular Geometry And Bond Angles:

XeO₂F₂ molecular geometry is originally said to be trigonal bipyramidal but due to the presence of lone pair on equatorial position, the actual shape will be see-sawed.

The repulsion between bond pair and lone pair of electrons will be more.

Here, fluorine will be axial atoms and oxygen will be equatorial atoms. As for the angles, the O–Xe–O angle will be 105.7°, O–Xe–F will be 91.6° and F–Xe–F will be 174.7°.

Additional Information

Hybridization of XeO2F2

In Xenon Dioxide Difluoride, xenon will be the central atom which will have 8 valence electrons. The fluorine atom will be the monovalent surrounding atom and the oxygen atom will be the divalent surrounding atom. We will take the eight valence electrons of Xenon and add 2 monovalent fluorine atoms. The whole sum will be divided by 2 at the end.

If we take the values then;

Number of electrons = [8 + 2-0 + 0] × 1/2 = 5 

We get 5 as the final number which further suggests sp³d hybridization.

In Xenon Dioxide Difluoride, there will be 5 sp³d hybrid orbitals. There are 5 electron pairs around the centre atom where it will contain 4 bond pairs and 1 lone pair.

Explanation-

The solubility of an element depends upon its polarity when dissolved in water. The more the size of an element the more polar that element. 

The more the size of an element then the more will be the orbitals present in it. Now due to more orbitals present in an element, the more will be the polarity of that element when it is dissolved in the solvent. And the more polarity of an element will result in more attraction between the solute molecules and the solvent molecule.

Hence, the intermolecular force of attraction between inert gas molecules and water molecules increases. Which will make the inert gas more soluble in water.

The size of the element increases with going down in a group in the periodic table. The helium atom is less in size than the neon and the size gets increasing further going down the group.

Hence, as per the size, the order will be Xe>Kr>Ar>Ne>He which is also the order of solubility in water.

Explanation-

⇒ An acid can be defined as a species that readily gives hydrogen ions in the solution. If the hydrogen atom is weakly bonded then it will be released easily, making the acid stronger in nature.

⇒Similarly, if the hydrogen atom is strongly bonded then it cannot be released easily, making the acid a weak acid.

Given data and Analysis-

Option 1: HI > HBr > HCI

⇒ HCl, HBr, and HI are binary acids within the same group. The atom bonded to hydrogen that is Cl, Br, and I respectively becomes larger as we proceed down the group, which tends to weaken the bond to H.

⇒ As a result, binary acids become more acidic as we move from top to bottom in the group. So, the correct order of acidic strength is: HI > HBr > HCl

Option 2: HIO4 > HBrO4 > HCIO4

⇒ These are oxyacids with the same number of oxygens but with different central atoms.

⇒ As the electronegativity of the central atom increases, the bond strength of O-H weakens, resulting in an increase in acidity. So, the correct order of acidic strength is: HIO4 < HBrO4 < HCIO4

So the order of acidic strength is not correct in option 2.

Option 3: HCIO4 > HCIO₃ > HCIO3

⇒ In the case of oxyacids, the H is always bonded to one of the oxygens.

⇒ In oxyacid series such as HCIO4, HCIO₃, and HCIO2 with the increase in the number of oxygens bonded to the central atom, the oxidation number of the central atom also increases.

⇒ This causes a weakening of the O-H bond strength. As a result, an increase in acidity. So, the correct order of acidic strength is:

HCIO4 > HCIO3 > HCIO3.

Option 4: HF > H2O > NH3

⇒ In hydrides, the acidity of the hydrides of the corresponding elements also increases with an increase in electronegativity of the element.

⇒ F is the most electronegativity followed by O, N. As a result, the acidity increases.

So, the correct order of acidic strength is: HF > H2O > NH3