2019 JAMB CHEMISTRY PAST QUESTIONS AND ANSWERS Leave a Comment / Jamb Chemistry / By Jamb Tutor Report a question What’s wrong with this question? You cannot submit an empty report. Please add some details. 0% 0 votes, 0 avg Created by Jamb TutorJamb Chemistry 2019 JAMB CHEMISTRY PAST QUESTIONS AND ANSWERS 1 / 40 Category: JAMB Chemistry 2019 1. $$\text{A secondary alkanol can be oxidized to give an?}$$ a) $$\text{Alkanone.}$$ b) $$\text{Alkyne.}$$ c) $$\text{Alkanoic acid.}$$ d) $$\text{Alkanal.}$$ $$\text{Secondary alkanols oxidize to alkanones through the loss of two hydrogen atoms or addition of oxygen.}$$ 2 / 40 Category: JAMB Chemistry 2019 2. $$\text{Which compound gives a precipitate with an aqueous solution of Cu(I) chloride?}$$ a) $$\text{But-2-ene.}$$ b) $$\text{But-1-ene.}$$ c) $$\text{But-2-yne.}$$ d) $$\text{But-1-yne.}$$ $$\text{But-2-yne reacts with Cu(I) chloride to form a reddish precipitate of copper acetylide.}$$ 3 / 40 Category: JAMB Chemistry 2019 3. $$\text{What is the IUPAC name of CH}_3\text{CH}_2\text{COOCH}_2\text{CH}_3?$$ a) $$\text{Methylpropanoate.}$$ b) $$\text{Ethylethanoate.}$$ c) $$\text{Ethylpropanoate.}$$ d) $$\text{Methylethanoate.}$$ $$\text{The compound is ethylpropanoate, a derivative of propanoic acid.}$$ 4 / 40 Category: JAMB Chemistry 2019 4. $$\text{A hydrocarbon produces 89.6 dm}^{3}\text{ of CO}_2\text{ and 54g of water on combustion. What is it?}$$ a) $$\text{C}_6\text{H}_6.}$$ b) $$\text{C}_4\text{H}_{10.}$$ c) $$\text{C}_5\text{H}_{10.}$$ d) $$\text{C}_4\text{H}_6.}$$ $$\text{C}_4\text{H}_{10}\text{ fits the combustion products, showing 10H atoms and 4C atoms.}$$ 5 / 40 Category: JAMB Chemistry 2019 5. $$\text{2-methylprop-1-ene is an isomer of?}$$ a) $$\text{3-methylbut-1-ene.}$$ b) $$\text{2-methylbut-1-ene.}$$ c) $$\text{But-2-ene.}$$ d) $$\text{Pent-2-ene.}$$ $$\text{3-methylbut-1-ene is the structural isomer of 2-methylprop-1-ene.}$$ 6 / 40 Category: JAMB Chemistry 2019 6. $$\text{Hydrocarbons reactive with Tollen’s reagent conform to which general formula?}$$ a) $$\text{C}_n\text{H}_{2n.}$$ b) $$\text{C}_n\text{H}_{2n+2.}$$ c) $$\text{C}_n\text{H}_{2n-2.}$$ d) $$\text{C}_n\text{H}_{2n+1}\text{OH.}$$ $$\text{C}_n\text{H}_{2n-2}\text{ corresponds to alkynes reactive with Tollen’s reagent.}$$ 7 / 40 Category: JAMB Chemistry 2019 7. $$\text{What is the IUPAC name of CF}_3\text{CHBrCl?}$$ a) $$\text{2-chloro-2-bromo-1,1,1-trifluoroethane.}$$ b) $$\text{2-bromo-2-chloro-1,1,1-trifluoroethane.}$$ c) $$\text{1-bromo-1-chloro-2,2,2-trifluoroethane.}$$ d) $$\text{1,1,1-trifluoro-2-bromo-2-chloroethane.}$$ $$\text{The correct IUPAC name is 2-bromo-2-chloro-1,1,1-trifluoroethane.}$$ 8 / 40 Category: JAMB Chemistry 2019 8. $$\text{Which polymer is not a synthetic rubber?}$$ a) $$\text{Neoprene.}$$ b) $$\text{Isoprene.}$$ c) $$\text{Butadiene.}$$ d) $$\text{Hexane.}$$ $$\text{Hexane is not involved in synthetic rubber production, unlike neoprene or isoprene.}$$ 9 / 40 Category: JAMB Chemistry 2019 9. $$\text{Burning magnesium removes which of these: O}_2, \text{N}_2, \text{Ar, CO}_2?$$ a) $$\text{O}_2\text{ and CO}_2.}$$ b) $$\text{O}_2, \text{N}_2, \text{Ar, CO}_2.}$$ c) $$\text{O}_2\text{ only.}$$ d) $$\text{O}_2\text{ and N}_2.}$$ $$\text{Burning magnesium primarily removes O}_2\text{ and CO}_2\text{ by reaction.}$$ 10 / 40 Category: JAMB Chemistry 2019 10. $$\text{Which trioxonitrate (V) compound is ideal for preparing oxygen?}$$ a) $$\text{Pb(NO}_3)_2.}$$ b) $$\text{Zn(NO}_3)_2.}$$ c) $$\text{Ca(NO}_3)_2.}$$ d) $$\text{Na(NO}_3).}$$ $$\text{Heating Pb(NO}_3)_2\text{ is effective for oxygen generation.}$$ 11 / 40 Category: JAMB Chemistry 2019 11. $$\text{Which metal regulates blood pressure and osmotic equilibrium?}$$ a) $$\text{Zinc.}$$ b) $$\text{Manganese.}$$ c) $$\text{Sodium.}$$ d) $$\text{Iron.}$$ $$\text{Sodium ions play a key role in blood pressure regulation and osmotic balance.}$$ 12 / 40 Category: JAMB Chemistry 2019 12. $$\text{Which alkaline earth metal reacts most spontaneously with water?}$$ a) $$\text{Calcium.}$$ b) $$\text{Beryllium.}$$ c) $$\text{Magnesium.}$$ d) $$\text{Strontium.}$$ $$\text{Strontium reacts more readily with water compared to other alkaline earth metals.}$$ 13 / 40 Category: JAMB Chemistry 2019 13. $$\text{What are the products of exposing chlorine water to sunlight?}$$ a) $$\text{HCl(aq) and Cl}_2.}$$ b) $$\text{HOCl(aq) and Cl}_2.}$$ c) $$\text{HCl(aq) and O}_2.}$$ d) $$\text{HOCl(aq) and O}_2.}$$ $$\text{HCl(aq) and O}_2\text{ are produced when chlorine water decomposes in sunlight.}$$ 14 / 40 Category: JAMB Chemistry 2019 14. $$\text{How does starch iodide paper turn blue-black with chlorine gas?}$$ a) $$\text{Chlorine attacks starch to form blue-black color.}$$ b) $$\text{Chlorine attacks iodide ion to form blue-black.}$$ c) $$\text{Chlorine oxidizes iodide to iodine, forming color.}$$ d) $$\text{Iodine directly reacts with starch for color.}$$ $$\text{Chlorine oxidizes iodide ions to iodine, which reacts with starch to form the blue-black complex.}$$ 15 / 40 Category: JAMB Chemistry 2019 15. $$\text{Which set consists of neutral oxides?}$$ a) $$\text{N}_2\text{O, H}_2\text{O, CO.}$$ b) $$\text{N}_2\text{O, SO}_2, CO.}$$ c) $$\text{N}_2\text{O, Na}_2\text{O, ZnO.}$$ d) $$\text{N}_2\text{O, SO}_3, NO.}$$ $$\text{N}_2\text{O, H}_2\text{O, and CO are neutral oxides as they do not react with acids or bases.}$$ 16 / 40 Category: JAMB Chemistry 2019 16. $$\text{Why is SO}_3\text{ not dissolved directly in water in H}_2\text{SO}_4\text{ production?}$$ a) $$\text{SO}_3\text{ is acidic.}$$ b) $$\text{Add acid to water, not vice versa.}$$ c) $$\text{Reaction is violently exothermic.}$$ d) $$\text{SO}_3\text{ is insoluble.}$$ $$\text{SO}_3\text{ reacts violently with water, releasing heat, making direct dissolution hazardous.}$$ 17 / 40 Category: JAMB Chemistry 2019 17. $$\text{Which statement does not align with Rutherford’s nuclear theory?}$$ a) $$\text{Contains protons/neutrons.}$$ b) $$\text{Positively charged.}$$ c) $$\text{Massive, deflects projectiles.}$$ d) $$\text{Large with most projectiles undeflected.}$$ $$\text{The nucleus is small, containing protons/neutrons; 98% projectiles pass undeflected.}$$ 18 / 40 Category: JAMB Chemistry 2019 18. $$\text{Elements X (1s}^2\text{2s}^2\text{2p}^4) \text{and Y (1s}^2\text{2s}^2\text{2p}^6\text{3s}^2\text{3p}^1) \text{combine to form}$$ \text{…}$$ a) $$\text{XY.}$$ b) $$\text{X}_2\text{Y.}$$ c) $$\text{Y}_2\text{X}_3.}$$ d) $$\text{X}_2\text{Y}_3.}$$ $$\text{X has valency 2, Y has valency 3, forming compound X}_2\text{Y}_3.}$$ 19 / 40 Category: JAMB Chemistry 2019 19. $$\text{What temperature change is needed to double pressure of 200 cm}^3$$ \text{Nitrogen at 27}^\circ\text{C if final volume is 150 cm}^3?$$ a) $$\text{150}^\circ\text{C.}$$ b) $$\text{177}^\circ\text{C.}$$ c) $$\text{75}^\circ\text{C.}$$ d) $$\text{120}^\circ\text{C.}$$ $$\text{Using gas laws: PV/T = constant, solve for temperature to maintain proportionality.}$$ 20 / 40 Category: JAMB Chemistry 2019 20. $$\text{Calculate volume after reacting 50 cm}^3\text{ CO with 100 cm}^3\text{ O}_2\text{: } 2\text{CO + O}_2\text{ → 2CO}_2.}$$ a) $$\text{75 cm}^3\text{.}$$ b) $$\text{125 cm}^3\text{.}$$ c) $$\text{100 cm}^3\text{.}$$ d) $$\text{50 cm}^3\text{.}$$ $$\text{50 cm}^3\text{ CO completely reacts with 25 cm}^3\text{ O}_2, leaving excess O}_2\text{ in final volume of 75 cm}^3\text{.}$$ 21 / 40 Category: JAMB Chemistry 2019 21. $$\text{What type of bond forms between NH}_3\text{ and H}^+\text{ to form NH}_4^+?$$ a) $$\text{Compound.}$$ b) $$\text{Ionic.}$$ c) $$\text{Covalent.}$$ d) $$\text{Electrovalent.}$$ $$\text{Dative bond forms as NH}_3\text{ donates a lone pair to H}^+.}$$ 22 / 40 Category: JAMB Chemistry 2019 22. $$\text{What types of bonds are present in NH}_4\text{Cl?}$$ a) $$\text{Ionic only.}$$ b) $$\text{Covalent only.}$$ c) $$\text{Ionic and covalent.}$$ d) $$\text{Dative covalent.}$$ $$\text{NH}_4^+\text{ has covalent and dative bonds, NH}_4\text{Cl is ionic.}$$ 23 / 40 Category: JAMB Chemistry 2019 23. $$\text{What happens to the reaction A + 2B → 2C + D when pressure decreases?}$$ a) $$\text{Equilibrium shifts.}$$ b) $$\text{Forward rate increases.}$$ c) $$\text{Backward rate increases.}$$ d) $$\text{Rates unaffected.}$$ $$\text{Lower pressure shifts equilibrium to more gaseous molecules. Forward reaction decreases.}$$ 24 / 40 Category: JAMB Chemistry 2019 24. $$\text{What is the equilibrium constant for xP + yQ ⇌ mR + nS?}$$ a) $$[\text{P}]^x[\text{Q}]^y.}$$ b) $$m[\text{R}][\text{S}]^x / [\text{P}]^y[\text{Q}].}$$ c) $$[\text{P}]^x[\text{Q}]^y[\text{R}]^m[\text{S}]^n.}$$ d) $$[\text{R}]^m[\text{S}]^n / [\text{P}]^x[\text{Q}]^y.}$$ `\text{Equilibrium constant K is derived as } [\text{R}]^m[\text{S}]^n / [\text{P}]^x[\text{Q}]^y.} 25 / 40 Category: JAMB Chemistry 2019 25. $$\text{Which of these reactions is an oxidation process?}$$ a) $$2\text{H}^+ + 2\text{e}^- → \text{H}_2.}$$ b) $$2\text{H}_2\text{O → 2H}_2\text{ + O}_2.}$$ c) $$2\text{H}_2\text{ + O}_2\text{ → 2H}_2\text{O.}$$ d) $$2\text{H}_2\text{O + 2e}^- → 2\text{OH}^-.}$$ $$\text{Water splitting 2H}_2\text{O → 2H}_2\text{ + O}_2\text{ involves oxidation of oxygen.}$$ 26 / 40 Category: JAMB Chemistry 2019 26. $$\text{What compound forms when Ba(OH)}_2\text{ reacts with NH}_4\text{Cl?}$$ a) $$\text{BaCl}_2.}$$ b) $$\text{Ba(NH}_4)_2.}$$ c) $$\text{Ba(NH}_4)_2\text{Cl}_2.}$$ d) $$\text{NH}_4\text{Cl.}$$ $$\text{NH}_4\text{Cl reacts to produce BaCl}_2\text{ and NH}_3\text{ gas.}$$ 27 / 40 Category: JAMB Chemistry 2019 27. $$\text{Which is not a transition metal characteristic?}$$ a) $$\text{Colored compounds.}$$ b) $$\text{Variable oxidation states.}$$ c) $$\text{High electronegativity.}$$ d) $$\text{Complex ion formation.}$$ $$\text{High electronegativity is not typical of transition metals.}$$ 28 / 40 Category: JAMB Chemistry 2019 28. $$\text{What is the oxidation state of P in PCl}_5?$$ a) $$\text{0.}$$ b) $$\text{+5.}$$ c) $$\text{-3.}$$ d) $$\text{+3.}$$ $$\text{Phosphorus has +5 in PCl}_5\text{ as all Cl atoms are -1.}$$ 29 / 40 Category: JAMB Chemistry 2019 29. $$\text{What forms when lithium reacts with water?}$$ a) $$\text{H}_2\text{O.}$$ b) $$\text{LiOH.}$$ c) $$\text{H}_2.}$$ d) $$\text{LiOH and H}_2.}$$ $$\text{Lithium reacts with water to form LiOH and H}_2\text{ gas.}$$ 30 / 40 Category: JAMB Chemistry 2019 30. $$\text{What is the temperature where evaporation equals condensation rate?}$$ a) $$\text{Boiling point.}$$ b) $$\text{Equilibrium point.}$$ c) $$\text{Melting point.}$$ d) $$\text{Critical point.}$$ $$\text{Boiling point is when rates equalize during phase change.}$$ 31 / 40 Category: JAMB Chemistry 2019 31. $$\text{What is the term for gas turning directly into solid?}$$ a) $$\text{Sublimation.}$$ b) $$\text{Deposition.}$$ c) $$\text{Condensation.}$$ d) $$\text{Evaporation.}$$ $$\text{Deposition is direct gas-to-solid phase transition.}$$ 32 / 40 Category: JAMB Chemistry 2019 32. $$\text{Which of these substances is liquid at room temperature?}$$ a) $$\text{Na.}$$ b) $$\text{Br}_2.}$$ c) $$\text{Cl}_2.}$$ d) $$\text{H}_2.}$$ $$\text{Bromine is a liquid nonmetal under standard conditions.}$$ 33 / 40 Category: JAMB Chemistry 2019 33. $$\text{What is the main component of natural gas?}$$ a) $$\text{Ethylene.}$$ b) $$\text{Methane.}$$ c) $$\text{Propane.}$$ d) $$\text{Butane.}$$ $$\text{Methane (CH}_4\text{) is the primary component of natural gas.}$$ 34 / 40 Category: JAMB Chemistry 2019 34. $$\text{What property measures an element’s ability to attract electrons?}$$ a) $$\text{Lose electrons.}$$ b) $$\text{Attract electrons.}$$ c) $$\text{Gain protons.}$$ d) $$\text{Conduct electricity.}$$ $$\text{Electronegativity indicates electron attraction strength.}$$ 35 / 40 Category: JAMB Chemistry 2019 35. $$\text{For } 2H}_2\text{ + O}_2\text{ → 2H}_2\text{O, which is true?}$$ a) $$\text{More reactant moles.}$$ b) $$\text{More product moles.}$$ c) $$\text{Endothermic.}$$ d) $$\text{Exothermic.}$$ $$\text{This exothermic reaction releases heat and is irreversible.}$$ 36 / 40 Category: JAMB Chemistry 2019 36. $$\text{What determines an element’s atomic number?}$$ a) $$\text{Neutrons.}$$ b) $$\text{Electrons.}$$ c) $$\text{Protons.}$$ d) $$\text{Isotopes.}$$ $$\text{Proton count defines atomic number.}$$ 37 / 40 Category: JAMB Chemistry 2019 37. $$\text{What is the name of the process for industrial ammonia production?}$$ a) $$\text{Haber process.}$$ b) $$\text{Haber-Bosch.}$$ c) $$\text{Ostwald.}$$ d) $$\text{Contact.}$$ $$\text{Haber process produces NH}_3\text{ from N}_2\text{ and H}_2.}$$ 38 / 40 Category: JAMB Chemistry 2019 38. $$\text{How is NaCl classified?}$$ a) $$\text{Covalent.}$$ b) $$\text{Ionic.}$$ c) $$\text{Metallic.}$$ d) $$\text{Molecular.}$$ $$\text{Sodium chloride (NaCl) is an ionic compound.}$$ 39 / 40 Category: JAMB Chemistry 2019 39. $$\text{What is true about isotopes?}$$ a) $$\text{Equal electrons.}$$ b) $$\text{Equal protons.}$$ c) $$\text{Different atomic masses.}$$ d) $$\text{Equal masses.}$$ $$\text{Isotopes have equal protons but varying neutrons.}$$ 40 / 40 Category: JAMB Chemistry 2019 40. $$\text{Which element has the highest ionization energy?}$$ a) $$\text{Na.}$$ b) $$\text{He.}$$ c) $$\text{Li.}$$ d) $$\text{Ne.}$$ $$\text{Helium (He) has the highest ionization energy.}$$ 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