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JEE Main Inorganic Chemistry: practice questions with solutions

15 questions on Chemical Bonding, Chemical Bonding (VSEPR), Coordination Compounds, Periodic Properties, d- and f-Block Elements, p-Block Elements, s-Block Elements. Try each one first, then open the solution.

Tip: solve on paper before opening a solution. Once you open it, that question is counted as practised and won't appear in your HeyGyan tests.
Chemical BondingMedium

Q1. Which species has a bond order of 2.5?

  1. O₂
  2. O₂⁺
  3. O₂⁻
  4. O₂²⁻
Show answer and solution

Answer: (B) O₂⁺

SolutionO₂ has bond order 2. Removing an antibonding π* electron raises it: O₂⁺ = 2.5. Adding electrons lowers it: O₂⁻ = 1.5, O₂²⁻ = 1.
Common trapO₂⁻ (1.5) is chosen by students who think adding electrons strengthens the bond.
Chemical Bonding (VSEPR)Medium

Q2. What is the shape of the XeF₄ molecule?

  1. Tetrahedral
  2. See-saw
  3. Square planar
  4. Square pyramidal
Show answer and solution

Answer: (C) Square planar

SolutionXe has 4 bond pairs and 2 lone pairs (6 electron domains, sp³d²). The lone pairs sit opposite each other, leaving a square planar shape.
Common trapTetrahedral is the shape for 4 bond pairs with no lone pairs.
Coordination CompoundsHard

Q3. What is the spin-only magnetic moment of [Fe(CN)₆]³⁻?

  1. 0 BM
  2. 1.73 BM
  3. 3.87 BM
  4. 5.92 BM
Show answer and solution

Answer: (B) 1.73 BM

SolutionFe³⁺ is d⁵. CN⁻ is a strong-field ligand, so the electrons pair up (t₂g⁵): 1 unpaired electron. μ = √(n(n+2)) = √3 ≈ 1.73 BM.
Common trap5.92 BM is the high-spin value, which applies to weak-field ligands like F⁻.
Periodic PropertiesMedium

Q4. Which is the correct order of ionic radii?

  1. N³⁻ > O²⁻ > F⁻ > Na⁺ > Mg²⁺
  2. Mg²⁺ > Na⁺ > F⁻ > O²⁻ > N³⁻
  3. F⁻ > O²⁻ > N³⁻ > Na⁺ > Mg²⁺
  4. N³⁻ > F⁻ > O²⁻ > Mg²⁺ > Na⁺
Show answer and solution

Answer: (A) N³⁻ > O²⁻ > F⁻ > Na⁺ > Mg²⁺

SolutionAll five ions have 10 electrons (isoelectronic). Radius falls as nuclear charge rises: N (7) > O (8) > F (9) > Na (11) > Mg (12).
Common trapRanking by number of electrons, which is the same for all five.
Coordination CompoundsMedium

Q5. What is the hybridisation of nickel in [Ni(CN)₄]²⁻?

  1. sp³
  2. dsp²
  3. sp³d
  4. d²sp³
Show answer and solution

Answer: (B) dsp²

SolutionNi²⁺ is d⁸. Strong-field CN⁻ pairs the electrons and frees one 3d orbital, giving dsp² hybridisation and a square planar, diamagnetic complex.
Common trapsp³ (tetrahedral) applies to [NiCl₄]²⁻, where Cl⁻ is a weak-field ligand.
p-Block ElementsMedium

Q6. Which oxoacid of phosphorus is monobasic?

  1. H₃PO₄
  2. H₃PO₃
  3. H₃PO₂
  4. H₄P₂O₇
Show answer and solution

Answer: (C) H₃PO₂

SolutionBasicity equals the number of P–OH groups. H₃PO₂ has one P–OH and two P–H bonds, so it is monobasic. H₃PO₃ has two P–OH (dibasic).
Common trapCounting all hydrogens. H atoms bonded directly to P are not acidic.
d- and f-Block ElementsEasy

Q7. Which aqueous ion has the highest spin-only magnetic moment?

  1. Cr³⁺
  2. Fe²⁺
  3. Mn²⁺
  4. Cu²⁺
Show answer and solution

Answer: (C) Mn²⁺

SolutionUnpaired electrons: Cr³⁺ (d³) 3, Fe²⁺ (d⁶) 4, Mn²⁺ (d⁵) 5, Cu²⁺ (d⁹) 1. Mn²⁺ has the most, so its moment is highest (5.92 BM).
Common trapPicking Fe²⁺ because it has more d-electrons. What matters is unpaired electrons.
Coordination CompoundsHardNumerical

Q8. How many stereoisomers does [Co(en)₂Cl₂]⁺ have in total?

Numerical value question: type the answer, no options.

Show answer and solution

Answer: 3

SolutionTrans form: has a mirror plane, so 1 isomer. Cis form: non-superimposable on its mirror image, so 2 optical isomers. Total = 3.
Common trapAnswering 2 by counting only cis and trans.
Chemical Bonding (VSEPR)HardNumerical

Q9. How many of these species are square planar? XeF₄, SF₄, [Ni(CN)₄]²⁻, [NiCl₄]²⁻, ICl₄⁻, BrF₄⁻, CCl₄

Numerical value question: type the answer, no options.

Show answer and solution

Answer: 4

SolutionSquare planar: XeF₄, ICl₄⁻ and BrF₄⁻ (4 bond pairs + 2 lone pairs each), and [Ni(CN)₄]²⁻ (dsp²). SF₄ is see-saw, [NiCl₄]²⁻ and CCl₄ are tetrahedral. Total = 4.
Common trapTreating SF₄ as square planar. It has only one lone pair.
Periodic PropertiesMedium

Q10. Which element has the most negative electron gain enthalpy?

  1. F
  2. Cl
  3. Br
  4. O
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Answer: (B) Cl

SolutionChlorine releases the most energy on gaining an electron. Fluorine is so small that the added electron faces strong repulsion from its compact 2p shell, so its value is less negative than chlorine's.
Common trapPicking fluorine because it is the most electronegative. Electronegativity and electron gain enthalpy are different properties.
Chemical Bonding (VSEPR)Medium

Q11. What is the shape of the ClF₃ molecule?

  1. Trigonal planar
  2. Trigonal pyramidal
  3. T-shaped
  4. See-saw
Show answer and solution

Answer: (C) T-shaped

SolutionCl has 3 bond pairs and 2 lone pairs (5 electron domains, sp³d). The lone pairs take equatorial positions, leaving a T-shaped molecule.
Common trapTrigonal planar is the shape for 3 bond pairs with no lone pairs, like BF₃.
Coordination CompoundsMedium

Q12. What is the IUPAC name of K₃[Fe(CN)₆]?

  1. Potassium hexacyanidoferrate(III)
  2. Potassium hexacyanidoiron(III)
  3. Potassium hexacyanidoferrate(II)
  4. Tripotassium hexacyanoiron
Show answer and solution

Answer: (A) Potassium hexacyanidoferrate(III)

SolutionThe complex ion is an anion, so the metal name ends in -ate (iron → ferrate). Charge balance: 3(+1) + x + 6(−1) = 0 gives x = +3, so Fe is +3.
Common trapUsing 'iron' instead of 'ferrate' for an anionic complex.
s-Block ElementsEasy

Q13. Which alkali metal ion has the highest hydration enthalpy?

  1. Li⁺
  2. Na⁺
  3. K⁺
  4. Cs⁺
Show answer and solution

Answer: (A) Li⁺

SolutionLi⁺ is the smallest ion, so its charge density is highest and it attracts water molecules most strongly.
Common trapPicking Cs⁺ because it is the largest. Larger ions hold water less tightly.
p-Block ElementsMedium

Q14. Which boron trihalide is the strongest Lewis acid?

  1. BF₃
  2. BCl₃
  3. BBr₃
  4. All are equal
Show answer and solution

Answer: (C) BBr₃

SolutionIn BF₃, fluorine donates electron density back to boron's empty p orbital (pπ–pπ back-bonding), which reduces its acidity. This back-bonding weakens down the group, so BBr₃ is the strongest acid.
Common trapPicking BF₃ because fluorine is the most electronegative.
d- and f-Block ElementsEasyNumerical

Q15. What is the oxidation state of chromium in K₂Cr₂O₇?

Numerical value question: type the answer, no options.

Show answer and solution

Answer: 6

Solution2(+1) + 2x + 7(−2) = 0, so 2x = 12 and x = +6.
Common trapForgetting that there are two chromium atoms gives +12.

Frequently asked questions

Which Inorganic Chemistry chapters are covered here?

This page covers Chemical Bonding, Chemical Bonding (VSEPR), Coordination Compounds, Periodic Properties, d- and f-Block Elements, p-Block Elements, s-Block Elements. Questions follow the JEE Main pattern, with multiple-choice and numerical value types.

Are these previous year JEE questions?

No. These are original JEE Main-level practice questions written on the latest pattern, with solutions and the common trap for each.