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% Created by Jamb TutorJamb Chemistry 2019 JAMB CHEMISTRY PAST QUESTIONS AND ANSWERS 1 / 40 Category: JAMB Chemistry 2019 1. A secondary alkanol can be oxidized to give an? a) Alkanone. b) Alkyne. c) Alkanoic acid. d) Alkanal. Secondary alkanols oxidize to alkanones through the loss of two hydrogen atoms or addition of oxygen. 2 / 40 Category: JAMB Chemistry 2019 2. Which compound gives a precipitate with an aqueous solution of Cu(I) chloride? a) But-2-ene. b) But-1-ene. c) But-2-yne. d) But-1-yne. But-2-yne reacts with Cu(I) chloride to form a reddish precipitate of copper acetylide. 3 / 40 Category: JAMB Chemistry 2019 3. What is the IUPAC name of $CH_3CH_2COOCH_2CH_3$? a) Methylpropanoate. b) Ethylethanoate. c) Ethylpropanoate. d) Methylethanoate. The compound is ethylpropanoate, a derivative of propanoic acid. 4 / 40 Category: JAMB Chemistry 2019 4. A hydrocarbon produces $89.6 dm^3$ of $CO_2$ and 54g of water on combustion. What is it? a) $C_6H_6$ b) $C_4H_{10}$ c) $C_5H_{10}$ d) $C_4H_6$ $C_4H_{10}$ fits the combustion products, showing 10H atoms and 4C atoms. 5 / 40 Category: JAMB Chemistry 2019 5. 2-methylprop-1-ene is an isomer of? a) 3-methylbut-1-ene. b) 2-methylbut-1-ene. c) But-2-ene. d) Pent-2-ene. 3-methylbut-1-ene is the structural isomer of 2-methylprop-1-ene. 6 / 40 Category: JAMB Chemistry 2019 6. Hydrocarbons reactive with Tollen’s reagent conform to which general formula? a) $C_nH_{2n}$ b) $C_nH_{2n+2}$ c) $C_nH_{2n-2}$ d) $C_nH_{2n+1}OH$ $C_nH_{2n-2}$ corresponds to alkynes reactive with Tollen’s reagent. 7 / 40 Category: JAMB Chemistry 2019 7. What is the IUPAC name of $CF_3CHBrCl$? a) 2-chloro-2-bromo-1,1,1-trifluoroethane. b) 2-bromo-2-chloro-1,1,1-trifluoroethane. c) 1-bromo-1-chloro-2,2,2-trifluoroethane. d) 1,1,1-trifluoro-2-bromo-2-chloroethane. The correct IUPAC name is 2-bromo-2-chloro-1,1,1-trifluoroethane. 8 / 40 Category: JAMB Chemistry 2019 8. Which polymer is not a synthetic rubber? a) Neoprene. b) Isoprene. c) Butadiene. d) Hexane. Hexane is not involved in synthetic rubber production, unlike neoprene or isoprene. 9 / 40 Category: JAMB Chemistry 2019 9. Burning magnesium removes which of these: $O_2$, $N_2$, Ar, $CO_2$? a) $O_2$ and $CO_2$ b) $O_2$, $N_2$, Ar, $CO_2$ c) $O_2$ only d) $O_2$ and $N_2$ Burning magnesium primarily removes $O_2$ and $CO_2$ by reaction. 10 / 40 Category: JAMB Chemistry 2019 10. Which trioxonitrate (V) compound is ideal for preparing oxygen? a) $Pb(NO_3)_2$ b) $Zn(NO_3)_2$ c) $Ca(NO_3)_2$ d) $Na(NO_3)$ Heating $Pb(NO_3)_2$ is effective for oxygen generation. 11 / 40 Category: JAMB Chemistry 2019 11. Which metal regulates blood pressure and osmotic equilibrium? a) Zinc. b) Manganese. c) Sodium. d) Iron. Sodium ions play a key role in blood pressure regulation and osmotic balance. 12 / 40 Category: JAMB Chemistry 2019 12. Which alkaline earth metal reacts most spontaneously with water? a) Calcium. b) Beryllium. c) Magnesium. d) Strontium. Strontium reacts more readily with water compared to other alkaline earth metals. 13 / 40 Category: JAMB Chemistry 2019 13. What are the products of exposing chlorine water to sunlight? a) HCl(aq) and $Cl_2$ b) HOCl(aq) and $Cl_2$ c) HCl(aq) and $O_2$ d) HOCl(aq) and $O_2$ HCl(aq) and $O_2$ are produced when chlorine water decomposes in sunlight. 14 / 40 Category: JAMB Chemistry 2019 14. How does starch iodide paper turn blue-black with chlorine gas? a) Chlorine attacks starch to form blue-black color. b) Chlorine attacks iodide ion to form blue-black. c) Chlorine oxidizes iodide to iodine, forming color. d) Iodine directly reacts with starch for color. Chlorine oxidizes iodide ions to iodine, which reacts with starch to form the blue-black complex. 15 / 40 Category: JAMB Chemistry 2019 15. Which set consists of neutral oxides? a) $N_2O$, $H_2O$, CO b) $N_2O$, $SO_2$, CO c) $N_2O$, $Na_2O$, ZnO d) $N_2O$, $SO_3$, NO $N_2O$, $H_2O$, and CO are neutral oxides as they do not react with acids or bases. 16 / 40 Category: JAMB Chemistry 2019 16. Why is $SO_3$ not dissolved directly in water in $H_2SO_4$ production? a) $SO_3$ is acidic. b) Add acid to water, not vice versa. c) Reaction is violently exothermic. d) $SO_3$ is insoluble. $SO_3$ reacts violently with water, releasing heat, making direct dissolution hazardous. 17 / 40 Category: JAMB Chemistry 2019 17. Which statement does not align with Rutherford’s nuclear theory? a) Contains protons/neutrons. b) Positively charged. c) Massive, deflects projectiles. d) Large with most projectiles undeflected. The nucleus is small, containing protons/neutrons; 98% projectiles pass undeflected. 18 / 40 Category: JAMB Chemistry 2019 18. Elements X $(1s^22s^22p^4)$ and Y $(1s^22s^22p^63s^23p^1)$ combine to form… a) XY b) $X_2Y$ c) $Y_2X_3$ d) $X_2Y_3$ X has valency 2, Y has valency 3, forming compound $X_2Y_3$ 19 / 40 Category: JAMB Chemistry 2019 19. What temperature change is needed to double pressure of 200 $cm^3$ Nitrogen at $27°C$ if final volume is 150 $cm^3$? a) $150°C$ b) $177°C$ c) $75°C$ d) $120°C$ Using gas laws: PV/T = constant, solve for temperature to maintain proportionality. 20 / 40 Category: JAMB Chemistry 2019 20. Calculate volume after reacting 50 $cm^3$ CO with 100 $cm^3$ $O_2$: $2CO + O_2 → 2CO_2$ a) 75 $cm^3$ b) 125 $cm^3$ c) 100 $cm^3$ d) 50 $cm^3$ 50 $cm^3$ CO completely reacts with 25 $cm^3$ $O_2$, leaving excess $O_2$ in final volume of 75 $cm^3$. 21 / 40 Category: JAMB Chemistry 2019 21. What type of bond forms between $NH_3$ and $H^+$ to form $NH_4^+$? a) Electrovalent. b) Compound. c) Ionic. d) Covalent. Dative bond forms as $NH_3$ donates a lone pair to $H^+$ 22 / 40 Category: JAMB Chemistry 2019 22. What types of bonds are present in $NH_4Cl$? a) Ionic only. b) Covalent only. c) Ionic and covalent. d) Dative covalent. $NH_4^+$ has covalent and dative bonds, $NH_4Cl$ is ionic. 23 / 40 Category: JAMB Chemistry 2019 23. What happens to the reaction A + 2B → 2C + D when pressure decreases? a) Equilibrium shifts. b) Forward rate increases. c) Backward rate increases. d) Rates unaffected. Lower pressure shifts equilibrium to more gaseous molecules. Forward reaction decreases. 24 / 40 Category: JAMB Chemistry 2019 24. What is the equilibrium constant for xP + yQ ⇌ mR + nS? a) $[P]^x[Q]^y$ b) $m[R][S]^x / [P]^y[Q]$ c) $[P]^x[Q]^y[R]^m[S]^n$ d) $[R]^m[S]^n / [P]^x[Q]^y$ Equilibrium constant K is derived as $[R]^m[S]^n / [P]^x[Q]^y$ 25 / 40 Category: JAMB Chemistry 2019 25. Which of these reactions is an oxidation process? a) $2H^+ + 2e^- → H_2$ b) $2H_2O → 2H_2 + O_2$ c) $2H_2 + O_2 → 2H_2O$ d) $2H_2O + 2e^- → 2OH^-$ Water splitting $2H_2O → 2H_2 + O_2$ involves oxidation of oxygen. 26 / 40 Category: JAMB Chemistry 2019 26. What compound forms when Ba(OH)$_2$ reacts with $NH_4Cl$? a) $BaCl_2$ b) $Ba(NH_4)_2$ c) $Ba(NH_4)_2Cl_2$ d) $NH_4Cl$ $NH_4Cl$ reacts to produce $BaCl_2$ and $NH_3$ gas. 27 / 40 Category: JAMB Chemistry 2019 27. Which is not a transition metal characteristic? a) Colored compounds. b) Variable oxidation states. c) High electronegativity. d) Complex ion formation. High electronegativity is not typical of transition metals. 28 / 40 Category: JAMB Chemistry 2019 28. What is the oxidation state of P in $PCl_5$? a) 0 b) 5 c) -3 d) 3 Phosphorus has +5 in $PCl_5$ as all Cl atoms are -1. 29 / 40 Category: JAMB Chemistry 2019 29. What forms when lithium reacts with water? a) $H_2O$ b) LiOH c) $H_2$ d) LiOH and $H_2$ Lithium reacts with water to form LiOH and $H_2$ gas. 30 / 40 Category: JAMB Chemistry 2019 30. What is the temperature where evaporation equals condensation rate? a) Boiling point. b) Equilibrium point. c) Melting point. d) Critical point. Boiling point is when rates equalize during phase change. 31 / 40 Category: JAMB Chemistry 2019 31. What is the term for gas turning directly into solid? a) Sublimation. b) Deposition. c) Condensation. d) Evaporation. Deposition is direct gas-to-solid phase transition. 32 / 40 Category: JAMB Chemistry 2019 32. Which of these substances is liquid at room temperature? a) Na b) $Br_2$ c) $Cl_2$ d) $H_2$ Bromine is a liquid nonmetal under standard conditions. 33 / 40 Category: JAMB Chemistry 2019 33. What is the main component of natural gas? a) Ethylene. b) Methane. c) Propane. d) Butane. Methane ($CH_4$) is the primary component of natural gas. 34 / 40 Category: JAMB Chemistry 2019 34. What property measures an element’s ability to attract electrons? a) Lose electrons. b) Attract electrons. c) Gain protons. d) Conduct electricity. Electronegativity indicates electron attraction strength. 35 / 40 Category: JAMB Chemistry 2019 35. For $2H_2 + O_2 → 2H_2O$, which is true? a) More reactant moles. b) More product moles. c) Endothermic. d) Exothermic. This exothermic reaction releases heat and is irreversible. 36 / 40 Category: JAMB Chemistry 2019 36. What determines an element’s atomic number? a) Neutrons. b) Electrons. c) Protons. d) Isotopes. Proton count defines atomic number. 37 / 40 Category: JAMB Chemistry 2019 37. What is the name of the process for industrial ammonia production? a) Haber process. b) Haber-Bosch. c) Ostwald. d) Contact. Haber process produces $NH_3$ from $N_2$ and $H_2$ 38 / 40 Category: JAMB Chemistry 2019 38. How is NaCl classified? a) Molecular. b) Covalent. c) Ionic. d) Metallic. Sodium chloride (NaCl) is an ionic compound. 39 / 40 Category: JAMB Chemistry 2019 39. What is true about isotopes? a) Equal electrons. b) Equal protons. c) Different atomic masses. d) Equal masses. Isotopes have equal protons but varying neutrons. 40 / 40 Category: JAMB Chemistry 2019 40. Which element has the highest ionization energy? a) Na b) He c) Li d) Ne Helium (He) has the highest ionization energy. Your score is The average score is 0% LinkedIn Facebook Twitter VKontakte 0% Restart quiz Anonymous feedback Send feedback
