Q: Which of the following metals give inflammable gas with both acid and base?

Sol.(d) Amphoteric metals like Be, Zn,Al,Sn,Pb etc give H2 gas (inflammable) with both acid and base.

Q: Which set of ions have same magnetic moment?

Sol. (b)Ions, having similar number of unpaired e−, have same magnetic moment.

Q: The correct order of acidic strength of the following is:

Sol.(a) Acidic strength of oxides depends on electronegativity of central atom. As electronegativity of central atom increases acidic strength also increases. Correct order of acidic strength is: SO2>P2O3>SiO2>Al2O3

Q: The value of IE1,IE2,IE3, and IE4 of an atom are 7.5eV,25.6eV,48.6eV and 170.6eV respectively The electronic configuration of the atom will be:

Sol.(b) The biggest jump occurs from IE3 to IE4 IE3<<IE4(IEn)(IEn+1)n( Valence e−)=3 Hence, the electronic configuration of the atom will be 1s22s22p63s23p1

Q: The correct order increasing radii is:

Sol.(a) Correct order of increasing radii are:- (a) Be+2<Mg+2<Na+ (b) Ca+2<K+<S−2 (c) F−<O−2<N−3 (d) O−2<S−2<As3−

Q: What will be the distance between H and Cl atom in HCl. The radius of hydrogen is 0.37A˚ and the radius of chlorine is 1.67A˚ ? (According to the concept of covalent radius)

Sol.(b) Bond length of single covalent bond =rA+rB− 0.09(ΔEN) Bond length (dH−Cl)=rH+rcl−0.09(ΔEN) rH=0.37A˚;rCl=1.67A˚ and ΔEN=3.0−2.1=0.9 dH−Cl=0.37+1.67−0.09(0.9) or, dH−Cl=2.04−0.08=1.96A˚

Q: The ionization energy of sodium is 495 kJ mol−1. How much energy is needed to convert atoms present in 2.3mg of sodium into sodium ions?

(b) Ionization energy of Na=495 kJ/mol No. of moles of Na in 2.3mg =232.3×10=10−4 moles For 1 mol, energy needed is 495 kJ Hence, for 10−4 mol, energy needed is 495×103×10−4 J=49.5 J

Question 1

Which of the following is incorrect match?

Accepted Answer

Sol.(c) Element, having Z=48, is Cd
It is member of group 12 or IIB and period 6th 
Element having electronic configuration (Xe)4f7 5 d16 s2 is a lanthanoid. All lanthanoids belong to group IIIB and period 6th .
Element having electronic configuration (Rn)6 d2 7 s2 is an actinoid. All actinoids belong to group IIIB and period 7th .
Element, having Z=56, is Ba. It is member of group 2 or IIA and period 6th .

Question 2

Which of the following metals give inflammable gas with both acid and base?

Accepted Answer

Sol.(d) Amphoteric metals like Be, Zn,Al,Sn,Pb etc give H2​ gas (inflammable) with both acid and base.

Question 3

Which of the following have an incorrect order of ionization energy:

Accepted Answer

Sol.(c) Due to lanthanoid contraction Pb has greater effective nuclear charge (zeff ​) than Sn hence, Pb (IE) >Sn (IE)
Na+has electronic configuration of noble gas hence,
Na+(IE)>Mg+(IE) 
Li+has electronic configuration of noble gas hence,
Li+(IE)>O+(IE) 
C+has greater effective nuclear charge (zeff​) than Be+hence,
Be+(IE)<C+(IE)

Question 4

Which set of ions have same magnetic moment?

Accepted Answer

Sol. (b)Ions, having similar number of unpaired e−, have same magnetic moment.

Question 5

The correct order of acidic strength of the following is:

Accepted Answer

Sol.(a) Acidic strength of oxides depends on electronegativity of central atom. As electronegativity of central atom increases acidic strength also increases.
Correct order of acidic strength is:
SO2​>P2​O3​>SiO2​>Al2​O3​

Question 6

Ionization energy of F−is 320 kJ mol−1. The electron gain enthalpy of fluorine would be:

Accepted Answer

Sol.(a) Ionization energy of F−is 320 kJ mol−1 F−(g)+320 kJ mol−1→F(g)+e−;ΔH=320 kJ mol−1
Equation for electron gain enthalpy of F is:
F(g)+e−→F−(g)+320 kJ mol−1;ΔH=−320 kJ mol−1​

Question 7

The value of IE1​,IE2​,IE3​, and IE4​ of an atom are 7.5eV,25.6eV,48.6eV and 170.6eV respectively The electronic configuration of the atom will be:

Accepted Answer

Sol.(b) The biggest jump occurs from IE3​ to IE4​
IE3​<<IE4​(IEn​)(IEn+1​)n( Valence e−)=3​
Hence, the electronic configuration of the atom will be 1s22s22p63s23p1

Question 8

The correct order increasing radii is:

Accepted Answer

Sol.(a) Correct order of increasing radii are:-
(a) Be+2<Mg+2<Na+
(b) Ca+2<K+<S−2
(c) F−<O−2<N−3
(d) O−2<S−2<As3−

Question 9

What will be the distance between H and Cl atom in HCl. The radius of hydrogen is 0.37A˚ and the radius of chlorine is 1.67A˚ ? (According to the concept of covalent radius)

Accepted Answer

Sol.(b) Bond length of single covalent bond =rA​+rB​− 0.09(ΔEN)
Bond length (dH​−Cl​)=rH​+rcl​−0.09(ΔEN)
rH​=0.37A˚;rCl​=1.67A˚ and ΔEN=3.0−2.1=0.9
dH−Cl​=0.37+1.67−0.09(0.9)
or, dH−Cl​=2.04−0.08=1.96A˚

Question 10

The ionization energy of sodium is 495 kJ mol−1. How much energy is needed to convert atoms present in 2.3mg of sodium into sodium ions?

Accepted Answer

(b) Ionization energy of Na=495 kJ/mol No. of moles of Na in 2.3mg =232.3×10​=10−4 moles
For 1 mol, energy needed is 495 kJ
Hence, for 10−4 mol, energy needed is 495×103×10−4 J=49.5 J

Question 11

The correct order of the second ionization potential of carbon, nitrogen, oxygen and fluorine is

Accepted Answer

Sol.(c) IE2​ of neutral element is IE1​ of cation having single positive charge. Hence, for order of IE2​, first put +1 charge to each element then write electronic configuration.From left to right in a period, IE1​ increases and fulfilled or half filled elements have greater IE1​ than adjacent elements. Hence, correct order of IE2​ is: C>N>F>O

Question 12

The electronegativity of the following elements increases in the order:

Accepted Answer

Correct order of electro negativity is:P<S<N<O

Question 13

The formation of the oxide ion, O2−(g), from oxygen atom requires first an exothermic and then an endothermic step as shown below : O(g)+e−→O−(g);Δeg​H=−141kJmol−1 O−(g)+e−→O2−(g);Δeg​H=+780kJmol−1 Thus process of formation of O2− in gas phase is unfavorable even O2− is isoelectronic with neon. It is due to the fact that:

Accepted Answer

(c) Process of formation of O2− ion in gaseous phase is unfavorable because O−ion (anion) resists addition of another e−due to repulsion hence, electron repulsion outweighs the stability gained by achieving noble gas configuration.

Question 14

Which is the correct in the following -

Accepted Answer

(b) The atomic radius decreases along the period. Also cations are always smaller than their parent atom and anions are always larger than their parent atom.

Question 15

Which oxide of ' N ' is isoelectronic with CO2​ :

Accepted Answer

(c) N2​O is isoelectronic with CO2​. Both have 22 electrons.

Question 16

Arrange Ce3+,La3+,Pm3 and Yb3+ in increasing order of their size -

Accepted Answer

(a) Lanthanide contraction is observed in these ions, i.e., ionic radius decreases as atomic number increases.

Question 17

In which of the following compounds chromium shows maximum radius:-

Accepted Answer

Sol.(d) In CrCl2​, oxidation state of chromium is +2 (minimum). Thus it will have maximum radius. As positive oxidation state increases, radius decreases.

Question 18

The IP1​,IP2​,IP3​,IP4​, and IP5​ of an element are 7.1,14.3,34.5,46.8,162.2eV respectively. The element is likely to be-

Accepted Answer

(b) The jump in IP values exist in IP5​ and thus removal of fifth electron occurs from inner shell. Thus element contains four electrons in its valence shell. It means the element belongs to the group 14.

Question 19

Following are ground state electronic configuration of some neutral atoms:

Accepted Answer

Sol. (i) Three electrons in 2p subshell (i.e. half filled) indicate for its greater stability while 6 electrons in 2p indicate for its maximum stability. Thus electronic configuration (c) having 1 electron in 3 s would require minimum IE
(ii) c<a<b<d (increasing order of IE)

Question 20

The atomic number of three elements A,B and C are a,a+1 and a+2,C is an alkali metal. In a compound of A and C, the nature of bonding is-

Accepted Answer

(c) If C is alkali metal, A should be halogen (nonmetal). Between metal and non-metal ionic bond is present.

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Solutions for Inorganic Chemistry for IIT JEE Main and Advanced by Vineet Agarwal

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