Ionic and Covalent Character

Q. Estimate the percentage ionic character of the $HBr$ molecule, given that the dipole moment $\left(\mu \right)$ is $0.72D$ and $HBr$ bond length $150pm$

Q.

Arrange the bonds in order of increasing ionic character in the molecules: LiF, $K_{2}O,N_2,S{O}_{2}andCl{F}_3$.

Q.

The experimental value of dipole moment of HCl is 1.03 D. The length of H−Cl bond is 1.275 A. The percentage ionic character of HCl is:

1. 43
2. 21
3. 17
4. 7

Q. Calculate the percent ionic character of $H-F$ bond.
Given: ${\chi }_H=2.1,{\chi }_F=4.0$

1. 43.04 %
2. 58.35 %
3. 34.28 %
4. 28.68 %

Q.

The radius of ${\mathrm{Na}}^{+}$ is $95\mathrm{pm}$ and that of ${\mathrm{Cl}}^{-}$ ion is $181\mathrm{pm}$. Hence, what will be the coordination number of ${\mathrm{Na}}^{+}$ ?

Q.

Question 3

Metal hydrides are ionic, covalent or molecular in nature. Among LiH, NaH, KH, RbH, CsH, the correct order of increasing ionic charcter is

(a) LiH > NaH > CsH > KH > RbH

(b) LiH < NaH < KH < RbH < CsH

(c) RbH > CsH > NaH > KH > LiH

(d) NaH > CsH > RbH > LiH > KH

Q.

What is ion polarization?

Q. Which of the following pairs of elements forms a compound with maximum ionic character?

1. $Na$ and $F$
2. $Cs$ and $F$
3. Na and C
4. $Cs$ and $I$

Q. Given below are two statements: one is labelled as Assertion A and the other is labelled as Reason R.

Assertion A : $LiF$ is sparingly soluble in water.
Reason R : The ionic radius of $L{i}^{+}$ ion is smallest among its group members, hence has least hydration enthalpy.

In the light of the above statements, choose the most appropriate answer from the options given below.

Q. Calculate the percentage covalent character in the H-Br bond.

Given the electronegativity of Hydrogen is 2.2 and Bromine is 3.0.

Enter the value rounded off to the nearest integer. ___

1. 15
2. 85
3. 84
4. 16

Q. Calculate the percent ionic character of $H-F$ bond.
Given: ${\chi }_H=2.1,{\chi }_F=4.0$

1. 43.04 %
2. 58.35 %
3. 34.28 %
4. 28.68 %

Q. If the electronegativity of atom A is 2.0 and atom B is 3.0, then what is the percentage ionic character of bond A-B?

1. 19.5 %
2. 87.5 %
3. 80.5 %
   
4. 12.5 %

Q. According to Fajans' rules, ionic bonds are formed when cations have a:

1. low positive charge and large size
2. low positive charge and small size
3. high positive charge and large size, and anions have a small size
4. low positive charge and large size, and anions have a small size

Q. The dipole moment of $NaCl$ molecule is $8.4\text{D}$ and its bond length is $2.1\stackrel{\circ }{\text{A}}$. The percentage ionic character in this molecule will be:

1. $50.25\%$
2. $60.30\%$
3. $83.33\%$
4. $100\%$

Q. Which of the following compounds has the highest percentage of ionic character?

1. $LiI$
2. $CsF$
3. $CsI$
4. $MgC{l}_2$

Q.

Which is more ionic ${\mathrm{PbCl}}_2\mathrm{or}{\mathrm{PbCl}}_4$?

Q.

Hanny - Smith formula for calculating the percentage of ionic character is

1. 16(x_A - x _B) - 3.5 (x_A - x_B)²

2. 16(x_A - x _B) + 3.5 (x_A - x_B)²

3. 16(x_A - x _B)² + 3.5 (x_A - x_B)²

4. 16(x_A - x _B)² - 3.5 (x_A - x_B)

Q. The correct order of the increasing ionic character is :

1. $BeC{l}_2<MgC{l}_2<CaC{l}_2<BaC{l}_2$
2. $BeC{l}_2<MgC{l}_2<BaC{l}_2<CaC{l}_2$
3. $BeC{l}_2<BaC{l}_2<MgC{l}_2<CaC{l}_2$
4. $BaC{l}_2<MgC{l}_2<CaC{l}_2<BeC{l}_2$

Q. The melting point of NaBr is $682{}^{\circ }C$ while that of NaF is $988{}^{\circ }C$. The principle reason behind the melting point of NaF being higher than that of NaBr is:

1. The two crystal are not isomorphous
2. The molar mass of $NaF$ is lower than that of $NaBr$
3. The internuclear distance $(r_c+r_a)$ of $NaBr$ is greater than $NaF$
4. The bond in $NaBr$ has a higher covalent character than the bond in $NaF$

Q. The properties of most of the ionic solids deviate from their ideal ionic character because the lattice undergoes some distortion. Cations are usually smaller than anions and have a higher effective nuclear charge. The outer electron cloud in a cation is more firmly held than in an anion. The loose electron cloud of an anion, when attracted by the electron cloud of a cation, gets distorted. This phenomenon is known as polarization. Due to this phenomenon, the electron cloud of an anion shifts towards the cation which decreases both the magnitude of positive charge on the cation and the negative charge on the anion. In other words, covalent character develops in the ionic bond.

Which of the following is an ionic compound?

1. $AlC{l}_3$
2. $Al{F}_3$
3. $Al{I}_3$
4. $AlB{r}_3$

Q. The dipole moment of $NaCl$ molecule is $8.4\text{D}$ and its bond length is $2.1\stackrel{\circ }{\text{A}}$. The percentage ionic character in this molecule will be:

1. $60.30\%$
2. $83.33\%$
3. $50.25\%$
4. $100\%$

Q. Amongst $LiCl$, $RbCl$, $BeC{l}_2$ and $MgC{l}_2$, maximum and minimum ionic character will be shown by the compounds:

1. $MgC{l}_2$, $BeC{l}_2$
2. $LiCl$, $MgC{l}_2$
3. $RbCl$, $BeC{l}_2$
4. $RbCl$, $MgC{l}_2$

Q. The correct order of the increasing ionic character is :

1. $BeC{l}_2<MgC{l}_2<CaC{l}_2<BaC{l}_2$
2. $BeC{l}_2<MgC{l}_2<BaC{l}_2<CaC{l}_2$
3. $BeC{l}_2<BaC{l}_2<MgC{l}_2<CaC{l}_2$
4. $BaC{l}_2<MgC{l}_2<CaC{l}_2<BeC{l}_2$

Q. Which of the following has the minimum ionic character?

1. $PbC{l}_2$
2. $NaCl$
3. $MgC{l}_2$
4. $SnC{l}_4$

Q. Which of the following compounds has the highest percentage of ionic character?

1. $LiI$
2. $MgC{l}_2$
3. $CsF$
4. $CsI$

Q. The dipole moment of $NaCl$ molecule is $9\text{D}$ and its bond length is $2.5\stackrel{\circ }{\text{A}}$. The percentage ionic character in this molecule will be

1. $50\%$
2. $60\%$
3. $75\%$
4. $100\%$

Q. The correct statement(s) about dipole moments of $R_{3}NO$ and $R_{3}PO$ is/are:

1. Dipole moment of $R_{3}NO>$ dipole moment of $R_{3}PO$
2. Dipole moment of $R_{3}NO<$ dipole moment of $R_{3}PO$
3. Experimental dipole moment of $R_{3}PO>$ theoretical dipole moment of $R_{3}PO$
4. Experimental dipole moment of $R_{3}PO<$ theoretical dipole moment of $R_{3}PO$

Q. Which of the following is more ionic in nature?

1. $Cu{F}_2$
2. $CuC{l}_2$
3. $CuB{r}_2$
4. None of these

Q. Statement 1: $AgI$ is less soluble in water than $AgF$ due to more polarization of $I^{-}$ ion in comparison to $F^{-}$ ion.
Statement 2: The melting point of $BaC{l}_2$ is higher than the melting point of $BeC{l}_2$ due to the greater ionic nature of $BaC{l}_2$.
Statement 3: The order of hydrated radii is: $A{l}^{3+}\left(aq\right)>M{g}^{2+}\left(aq\right)>N{a}^{+}\left(aq\right)$

1. T T T
2. T T F
3. T F T
4. F T T

Q. Which of the following is/are correct order of solubility in water?

1. $LiI<LiBr<LiCl<LiF$
2. $Be(OH{)}_2<Mg(OH{)}_2<Ca(OH{)}_2<Sr(OH{)}_2<Ba(OH{)}_2$
3. $NaHC{O}_3<KHC{O}_3<RbHC{O}_3<CsHC{O}_3$
4. $Hg{F}_2>HgC{l}_2>HgB{r}_2>Hg{I}_2$