JEE Advanced (One or More Correct Option): Chemical Bonding & Molecular Structure

Q.1. The statements that are true among the followings are
(a) The bond order in CO molecule is 3
(b) The order of stability is
(c) KHF₂, KHCl₂ and KHBr₂ are known but KHI2 is not
(d) NO is paramagnetic while NO⁺ is diamagnetic

Correct Answer is option (a, d) 
Bond order O₂^-2 = 1
O₂^- = 1.5
O₂ = 2
O₂⁺ = 2.5
∴ stability; O₂⁺ > O₂ > O₂^- > O₂^-2

Q.2. KCl has a dipole moment of 10 D. The inter ionic distance in KCl is 2.6 Å. Which of the following statements are true for this compound?
(a) The theoretical value of dipole moment, if the compound were completely ionic is 12.5 D.
(b) The % ionic character of the compound is 85 %.
(c) It is a poor conductor of electricity.
(d) The forces operating in this molecule are coulombic type.

Correct Answer is option (a, c, d) 
μ = q × d = 4. 8 ×10^-10 × 2.6 × 10^-8 esu unit
= 12.48 D ~ 12.5 D
(In case of 100% ionic character)
% Ionic character

Q.3. Which of the following statements is/are true for P₄S³ molecule?
(a) It contains six P-S bonds and three P-P-bonds
(b) It contains six P-S bonds and ten lone pairs
(c) It has all atoms sp³-hybridised
(d) It contains six P-P bonds and ten lone pairs

Correct Answer is option (a, b, c) 

Q.4. Which of the following is/are correct?
(a) Ammonium salts are more soluble than sodium salts
(b) SnCl₂ is more ionic than SnCl₄ 
(c) Calcium fluoride is more ionic than calcium chloride.
(d) The formal charge on S atom in SO₂ is four

Correct Answer is option (a, b, c) 
Because of the H-bonding  is more extensively solvated than Na⁺ , hence  salts is more soluble than Na⁺ salts.
The polarising power of Sn⁴⁺ is greater than Sn²⁺ , hence SnCl₄ is more covalent The polarisibility of Cl^- is greater than F^- because of greater size.

In SO₂ , formal charge of

Q.5. Which of the following order of solubilities is/are correct?
(a) LiF < LiCl < LiBr < LiI
(b) LiF < NaF < KF < RbF
(c) CsI < CsBr < CsCl < CsF
(d) CsI < KI < NaI < LiI

Correct Answer is option (a, b, c, d) 
If the size of common ion is smaller, then greater the size of other ion more will be the solubility. If the size of common ion is bigger, then smaller the size of other ion more will be the solubility.

Q.6. Which of the following molecules has as O-O bond?
(a) H₂S₂O₈
(b) H₂S₂O₇
(c) H₂SO₅ 
(d) H₂S₂O₆ 

Correct Answer is option (a, c) 

Q.7. Which of the following species is paramagnetic?
(a) CN^- 
(b) NO
(c) O₂^2- 
(d) O₂

Correct Answer is option (b, d) 
CN^- isoelectronic with N₂, diamagnetic,
O₂^-2 isoelectronic with F₂, diamagnetic ,
O₂ → 2e^- unpaired in π* orbital
NO → 15 electron paramagnetic

Q.8. Correct statements are:
(a) I.E. for hydrogen atom = 13.6 ev
(b) I.E. of Li²⁺ in the first excited state is 30.6eV
(c) I.E. of Be³⁺ in the first excited state is 54.4 eV
(d) I.E. of Li²⁺ in the first excited state in 10.6 eV

Correct Answer is option (a, b, c) 

(a) E₁ for H = -13.6 eV
(b) I.E. for LI⁺² in 1^ST exited state
(c) I.E of BE⁺³ in 1^ST excited state

Q.9. Which of the molecules is/are planar?
(a) F₂C = C= CF₂ 
(b) F₂B - C= C - BF₂
(c) (SiH₃)₃N
(d) H₂N - NH₂ 

Correct Answer is option (a, b, c) 
In F₂C = C= CF₂ 
Terminal C-atoms are sp² hybridised, one sp² hybridised orbital comes in the horizontal plane and other sp² hybridised orbital appears on the vertical plane.

Q.10. Which of the following is correct?
(a) Ionic bond is non directional
(b) Ionic compound has very high boiling and melting point
(c) Ionic bond is form by transfer of electrons from one atom to another atom
(d) Boiling point of ionic compound is very low 

Correct Answer is option (a, b, c) 
Boiling point of ionic compound is very high because oppositely charged ions are healed together by very strong electrostatic attraction forces.