ECAT — Engineering College Admission Test (UET)

ECAT Chemistry — Transition Elements and Industrial Chemistry (Set 2)

Take the ECAT Chemistry — Transition Elements and Industrial Chemistry (Set 2): 30 multiple-choice questions (40 minutes) with instant scoring and a full…

What this test covers

30 ECAT Chemistry

Sample questions with answers

The first 5 questions of this test, with the correct answer and explanation.

Q1. The spin-only magnetic moment of Cr³⁺ (Z of Cr = 24) is about:
- A. 1.73 BM
- B. 4.90 BM
- C. 2.83 BM
- D. 3.87 BM ✓
Answer: D. 3.87 BM
Explanation: Cr³⁺ is 3d³ with n = 3 unpaired electrons; μ = √(n(n+2)) = √15 ≈ 3.87 BM.
Q2. A divalent 3d-metal ion has a spin-only magnetic moment of 2.83 BM. The ion is:
- A. Zn²⁺
- B. Mn²⁺
- C. Cu²⁺
- D. Ni²⁺ ✓
Answer: D. Ni²⁺
Explanation: √(n(n+2)) = 2.83 gives n = 2 unpaired electrons; Ni²⁺ (3d⁸) has two. Mn²⁺ has 5, Cu²⁺ has 1 and Zn²⁺ has 0.
Q3. Zinc, cadmium and mercury are not regarded as typical transition elements because:
- A. They form coloured compounds
- B. They have completely filled d subshells in the atom and in their common ions ✓
- C. They are non-metals
- D. They have no s electrons
Answer: B. They have completely filled d subshells in the atom and in their common ions
Explanation: Zn²⁺, Cd²⁺ and Hg²⁺ are d¹⁰; with no partly filled d orbitals they are colourless, diamagnetic and show essentially one oxidation state.
Q4. Transition metals and their compounds are good catalysts mainly because they:
- A. Can show variable oxidation states and provide surfaces for adsorption ✓
- B. Are all strongly coloured
- C. Are highly reactive towards water
- D. Have very low melting points
Answer: A. Can show variable oxidation states and provide surfaces for adsorption
Explanation: Variable oxidation states allow easy electron transfer (e.g. V₂O₅ in the contact process), and vacant d orbitals help adsorb reactants on the surface.
Q5. The square planar complex [Pt(NH₃)₂Cl₂] exists in two forms, one of which (cisplatin) is an anticancer drug. These two forms are:
- A. Optical isomers
- B. Cis and trans geometrical isomers ✓
- C. Ionization isomers
- D. Linkage isomers
Answer: B. Cis and trans geometrical isomers
Explanation: In a square planar MA₂B₂ complex the two Cl ligands can be adjacent (cis) or opposite (trans), giving two geometrical isomers.

The other 25 questions

Take the timed test (free, no sign-up) to see your score and the answer and explanation for every question.

Q6. The complex ion [Ag(NH₃)₂]⁺ has a coordination number and geometry of:
- A. 4, tetrahedral
- B. 2, bent
- C. 6, octahedral
- D. 2, linear
Q7. EDTA⁴⁻ forms very stable complexes with metal ions because it is a:
- A. Hexadentate chelating ligand
- B. Bidentate ligand
- C. Neutral ligand
- D. Monodentate ligand
Q8. The complex [Ni(CN)₄]²⁻ is diamagnetic. Its geometry and hybridization are:
- A. Linear, sp
- B. Square planar, dsp²
- C. Octahedral, d²sp³
- D. Tetrahedral, sp³
Q9. How many ions are produced in solution when one formula unit of [Co(NH₃)₆]Cl₃ dissolves?
- A. 4
- B. 7
- C. 3
- D. 2
Q10. In the blast furnace, the main reducing agent that converts iron oxides into iron is:
- A. Hydrogen
- B. Limestone
- C. Carbon monoxide
- D. Silica
Q11. Rust is best described as:
- A. FeO
- B. Hydrated iron(III) oxide, Fe₂O₃·xH₂O
- C. Fe₃O₄
- D. FeCO₃
Q12. A tin-plated iron can rusts faster than unplated iron once the tin coating is scratched because:
- A. Tin is more reactive than iron
- B. Tin dissolves in water
- C. Iron is more reactive than tin, so it becomes the anode and corrodes
- D. Tin catalyses the formation of rust
Q13. When KOH is added to an orange solution of K₂Cr₂O₇, the solution turns yellow because:
- A. Cr₂O₇²⁻ is reduced to Cr³⁺
- B. Cr₂O₇²⁻ is converted into CrO₄²⁻
- C. K₂O is formed
- D. Chromium is oxidized to +7
Q14. In neutral or weakly alkaline solution, MnO₄⁻ is reduced to MnO₂. The number of electrons gained per MnO₄⁻ ion is:
- A. 1
- B. 2
- C. 5
- D. 3
Q15. The equivalent mass of KMnO₄ (M = 158) when it acts as an oxidizing agent in acidic medium is:
- A. 79
- B. 158
- C. 52.7
- D. 31.6
Q16. What volume of 0.02 M KMnO₄ is needed to oxidize 25 cm³ of 0.1 M FeSO₄ in acidic solution?
- A. 125 cm³
- B. 12.5 cm³
- C. 50 cm³
- D. 25 cm³
Q17. The percentage of nitrogen in ammonium sulphate, (NH₄)₂SO₄, is about:
- A. 35.0%
- B. 46.7%
- C. 21.2%
- D. 10.6%
Q18. Single superphosphate fertilizer, made by treating rock phosphate with H₂SO₄, is a mixture of:
- A. H₃PO₄ and CaO
- B. Ca(H₂PO₄)₂ and CaSO₄
- C. NH₄H₂PO₄ and (NH₄)₂SO₄
- D. Ca₃(PO₄)₂ and CaCO₃
Q19. The two main raw materials for the manufacture of Portland cement are:
- A. Limestone (calcareous) and clay (argillaceous)
- B. Gypsum and coke
- C. Bauxite and iron ore
- D. Sand and soda ash
Q20. The major component of ordinary Portland cement by mass is:
- A. Silica (SiO₂), about 60–67%
- B. Iron oxide, about 30%
- C. Lime (CaO), about 60–67%
- D. Alumina (Al₂O₃), about 40%
Q21. The main chemical constituent of paper pulp is:
- A. Protein
- B. Cellulose
- C. Starch
- D. Lignin
Q22. In petroleum refining, catalytic reforming is used to:
- A. Break heavy oils into lighter fractions
- B. Remove sulphur compounds
- C. Convert straight-chain alkanes into branched alkanes and aromatics with higher octane numbers
- D. Separate crude oil into fractions by boiling point
Q23. Tetraethyl lead was formerly added to petrol in order to:
- A. Reduce knocking in engines
- B. Raise its boiling point
- C. Lower its density
- D. Remove sulphur
Q24. Chlorofluorocarbons (CFCs) harm the environment mainly because in the stratosphere they:
- A. Absorb all ultraviolet light
- B. Produce acid rain
- C. Release chlorine atoms that destroy ozone
- D. Increase the amount of oxygen
Q25. Carbon monoxide is poisonous because it:
- A. Reacts with water in the lungs to form an acid
- B. Forms a stable complex with haemoglobin and prevents oxygen transport
- C. Destroys red blood cells
- D. Is a strong oxidizing agent
Q26. What mass of iron is present in 116 g of magnetite, Fe₃O₄ (Fe = 56, O = 16)?
- A. 84 g
- B. 56 g
- C. 72 g
- D. 112 g
Q27. Assuming complete conversion, the mass of NH₃ formed from 6 g of H₂ and excess N₂ (N₂ + 3H₂ → 2NH₃) is:
- A. 17 g
- B. 68 g
- C. 51 g
- D. 34 g
Q28. The heating elements of electric heaters are commonly made of nichrome, an alloy of:
- A. Nickel and chromium
- B. Nickel and copper
- C. Iron and carbon only
- D. Chromium and cobalt
Q29. In the octahedral complex [Fe(CN)₆]³⁻, the oxidation state of iron and the number of unpaired electrons (strong-field ligand) are:
- A. +6 and 0
- B. +3 and 5
- C. +2 and 0
- D. +3 and 1
Q30. Which statement about the d-block elements is correct?
- A. They show only one oxidation state
- B. Most form coloured ions and complex compounds
- C. Their atomic radii increase sharply across a period
- D. They have low densities and low melting points