CHEMISTRY 2023 UTME PAST QUESTION

1. Which of the following elements will exhibit the most electronegative character?

A. Al
B. Si
C. P
D. S

2. Acid hydrolysis of nitriles will yield?

A. Alkanes
B. Aldehydes
C. Carboxylic acid
D. Alcohols

3. How many isomers of C4H9OH will be tertiary alkanol?

A. 1
B. 2
C. 3
D. 4

4. Which of the following makes oils distinguished from fats?

A. Oil contains a higher proportion of unsaturation.
B. Fats contain a higher proportion of unsaturation.
C. Oil and fats have the same proportion of unsaturation
D. Neither oil nor of unsaturation

5. The characteristic crystalline shape of solid water is due to:

A. Covalent bond
B. Hydrogen bonds
C. Ionic bonds
D. Metallic bonds

6. The chemical formula for laughing gas is:

A. NO
B. NO₂
C. N₂O
D. N₂O₅

7. The sulphide used in coating electric fluorescent tubes is:

A. Iron (III) sulphide
B. Sphalerite
C. Zinc sulphide
D. Sulphide mineral

8. Calculate the volume in dm3 of oxygen evolved at s. t. p. when a current of 5A is passed through acidified water for 772s (molar volume of gas at stp. = 22.4 dm3

A. 0.056
B. 0.224
C. 224000
D. 56000

9. Hydrogenation of Benzene to cyclohexane is called:

A. Cracking
B. Polymerization
C. Reforming
D. Aromatization

10. The pollutant that contribute to the depletion of the ozone layer is:

A. CF
B. CS
C. CCI
D. CFC

11. What changes sodium hydroxide pellets to liquid?

A. Oxygen
B. Water vapor
C. Carbon
D. Nitrogen

12. The compound used as “antifreeze” in car radiators in cold regions of the world is:

A. Ethanol
B. Ethylene glycol
C. Ethanal
D. Propan-1,2-diol

13. What are the laws that form the general gas equation?

A. Boyle’s and Charles law
B. Boyle’s Charles and Graham’s laws
C. Boyle’s law only
D. Charles and Graham’s law

14. Chlorine, bromine, and iodine resemble each other in that all:

A. Dissolve in alkali
B. Displace each other from solutions of their salts
C. React violently with hydrogen on heating
D. Are electron donors

15. The method suitable for separating suspended particles in liquid is:

A. Decantation
B. Distillation
C. Centrifugation
D. Chromatography

16. A hydrocarbon X has a molar mass of 26 and a carbon atom percentage of 92.3%. What is its molecular formula?

A. C₂H₂
B. C₂H₆
C. CH₄
D. C₃H₈

17. Silica gel, when exposed to air, turns liquid. What kind of substance is it?

A. Deliquescent
B. Hygroscopic
C. Efflorescent
D. Evaporation

18. In an equilibrium reaction, which of the following conditions indicates that the maximum yield of the product will be obtained?

A. Equilibrium constant is very large
B.▲H = T▲S
C.▲H > T▲S
D. Equilibrium constant is less than zero

19. Under high pressure, real gases do not obey gas laws because more energetic

A. Have become more energetic
B. Have become less energetic
C. Have become less in Size
D. Have become larger in size

20. The salt responsible for temporary hardness is:

A. Calcium sulphate
B. Magnesium chloride
C. Calcium bicarbonate
D. Magnesium sulphate

21. Common salt (NaCl) is used to preserve foods. Which of the following properties can be used to determine its purity before use?

A. Solubility in water
B. Melting point
C. Relative density
D. Crystalline nature

22. The rate of a chemical reaction is NOT affected by one of these factors:

A. Color
B. Concentration
C. Presence of light
D. Surface area

23. The functional group represented in the compound above is:

A. Alkanol
B. Alkanal
C. Alkanone
D. Alkanoate

24. On exposure to the atmosphere, a hydrated salt loses its water of cyclization to become anhydrous. This phenomenon is referred to as:

A. Efflorescence
B. Deliquescence
C. Hygroscope
D. Hydrolysis

25. Which of the following statements is true of the electrochemical series?

A. Electropositivity of metals increases down the series
B. Electropositivity of non-metals decreases down the series
C. Electronegativity of non-metals decreases
D. Electropositivity of metals decreases down the series

26. Which of th4e following pairs are both substances deliquescent?

A. CaCl₂ and H₂SO₄
B. NaOH and MgSO₄.7H₂O
C. CaCl₂ and NaOH
D. CuO and NaCl

27. The bond formed between H2O AND H⁺ to form the hydroxonium H₃O⁺ is:

A. Dative bond
B. Covalent bond
C. Electrovalent bond
D. Ionic bond

28. Gas molecules are said to be perfectly elastic because:

A. They collide without loss of energy
B. They move about in straight lines
C. The distances between them are negligible
D. The volume occupied by them is negligible

29. A solid that absorbs water from the atmosphere and forms an aqueous solution is:

A. Hydrophilic
B. Efflorescent
C. Deliquescent
D. Hygroscopic

30. Which of the following can undergo both addition reaction and substitution reaction?

A. Benzene
B. Pentane
C. Propane
D. Hexane

31. Naming of the organic compound CH₃(CH₂)₄CH₂CH₂NH₂:

A. Pentane-amine
B. Heptane-amine
C. Hexamine
D. Octane-amine

32. 2Cl− ═ Cl_2(g) + 2e⁻ _(aq) ^.s

The above half-cell reaction occurring at the anode during the electrolysis of dilute ZnCl2 solution is?

A. Ionization
B. Oxidation
C. Reduction
D. Recombination

33. CHCl₃+ Cl₂→ HCl + CCl₄.

A. An addition reaction
B. A decomposition reaction
C. A substitution reaction
D. A condensation reaction

34. C_xH_y + 4O₂ ═ 3CO₂+ 2H₂O

The hydrocarbon, CxHy, in the reaction above is?

A. Butene
B. Butane
C. Butyne
D. Butanone

35. One method of driving the position of equilibrium of an endothermic reaction forward is to?

A. Increases temperature at constant pressure
B. Decrease pressure at constant temperature
C. Cool down the apparatus with water
D. Decreases temperature at constant pressure

36. 0.92g of ethanol when burned raised the temperature of 50g of water by 28.6k. Calculate the heat of combustion of ethanol. [C = 12, 0 = 16, H = 1, Specific heat capacity of water = 4.2 Jg-1 K-1]

A. +3000 KJmol^-1
B. +300 KJmol^-1
C. -300 KJmol^-1
D. -3000 KJmol^-1

37. The repeating unit in natural rubber is

A. alkyne
B. isoprene
C. n-propene
D. neoprene

38. What current in amperes will deposit 2.7g of aluminum in 2 hours? [Al = 2.7, F = 96500 C mol-1]

A. 32
B. 8
C. 4
D. 16

39. Steam changes the color of anhydrous cobalt (II) chloride from

A. Blue to pinks
B. Red to white
C. White to green
D. White to blue

40. Which of the following will change when a catalyst id added to a chemical reaction?

A. The activation energy
B. The potential energy of the reactions
C. The heat of the reaction
D. The potential energy of the product