Q.14 Match the molecules in Group I with the type of bonds present in them, in Group
II
Group I Group II
P) NaCl 1) Coordination bond
Q) H2 2) Polar covalent bond
R) Pd–P bond in Pd(PPh3)4 3) Covalent bond
S) C–Cl bond in CH3Cl 4) Ionic bond
(A) P–4, Q–1, R–3, S–2
(B) P–2, Q–3, R–1, S–4
(C) P–4, Q–3, R–1, S–2
(D) P–4, Q–3, R–2, S–1
Correct Answer: (C) P-4, Q-3, R-1, S-2
NaCl features an ionic bond due to complete electron transfer from sodium to chlorine. H2 contains a non-polar covalent bond from equal electron sharing between identical atoms. The Pd-P bond in Pd(PPh3)4 forms a coordination bond via phosphorus lone pair donation to palladium. The C-Cl bond in CH3Cl is polar covalent owing to chlorine’s higher electronegativity creating uneven electron distribution.
Bond Analysis
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P) NaCl: Sodium (metal) loses one valence electron to chlorine (non-metal), forming Na⁺ and Cl⁻ ions held by electrostatic attraction—this defines an ionic bond (matches 4).
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Q) H2: Two hydrogen atoms share one electron pair equally, as both have identical electronegativity (2.1), resulting in a pure covalent bond (matches 3).
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R) Pd-P in Pd(PPh3)4: Triphenylphosphine (PPh3) acts as a ligand; phosphorus’s lone pair donates to empty Pd orbital, forming a dative/coordination bond (matches 1).
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S) C-Cl in CH3Cl: Electronegativity difference (C: 2.5, Cl: 3.0) of 0.5 yields polar covalent bonding with partial charges (matches 2).
Option Breakdown
| Option | P (NaCl) | Q (H2) | R (Pd-P) | S (C-Cl) | Correct? |
|---|---|---|---|---|---|
| (A) | 4 (✓) | 1 (✗) | 3 (✗) | 2 (✓) | No |
| (B) | 2 (✗) | 3 (✓) | 1 (✓) | 4 (✗) | No |
| (C) | 4 (✓) | 3 (✓) | 1 (✓) | 2 (✓) | Yes |
| (D) | 4 (✓) | 3 (✓) | 2 (✗) | 1 (✗) | No |
Introduction to Bond Types Matching in CSIR NET
CSIR NET aspirants often face matching questions on NaCl H2 Pd(PPh3)4 CH3Cl bond types, testing ionic, covalent, coordination, and polar covalent bonds. This question (Q.14) from competitive exams like CSIR NET Chemical Sciences evaluates core concepts in chemical bonding. Understanding these distinctions aids in molecular biology, biochemistry, and inorganic chemistry prep.
Key Bond Types Explained
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Ionic Bond (NaCl): Electron transfer between metal (Na) and non-metal (Cl) creates oppositely charged ions.
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Covalent Bond (H2): Equal sharing of electrons between identical atoms forms a stable sigma bond.
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Coordination Bond (Pd-P in Pd(PPh3)4): Ligand (PPh3) donates lone pair to central metal (Pd), common in organometallics.
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Polar Covalent Bond (C-Cl in CH3Cl): Unequal sharing due to electronegativity difference (ΔEN ≈ 0.5-1.7).
CSIR NET Question Solution
Group I matches Group II as P-4 (ionic), Q-3 (covalent), R-1 (coordination), S-2 (polar covalent), confirming option (C). This aligns with standard classifications in exam syllabi.
Exam Tips for Bonding Questions
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Recall electronegativity scales for polar vs. non-polar classification.
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Identify coordination bonds in complexes like Pd(PPh3)4 catalysts.
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Practice similar match-the-following for CSIR NET Life/Chemical Sciences.
