POST UTME EKSU 2025 Chemistry | Objective

Practice these randomly selected questions to test your readiness.

Question 1
Determine the pH of a 0.1 M solution of HCl.
A. 1
B. 2
C. 3
D. 4
Question 2
A 2.50-g sample of a metal oxide is treated with excess hydrochloric acid to produce 1.25 L of hydrogen gas at 25°C and 1 atm. What is the molar mass of the metal oxide?
A. 100 g/mol
B. 150 g/mol
C. 200 g/mol
D. 250 g/mol
Question 3
A 1.0 M solution of Ca(OH)2 is mixed with a 1.0 M solution of HNO3. If the reaction is allowed to proceed to completion, what is the concentration of the remaining Ca(OH)2?
A. 0.5 M
B. 0.75 M
C. 1.0 M
D. 1.25 M
Question 4
A 100 mL sample of a solution containing 0.5 M NH₃ is treated with 10 mL of 0.5 M HCl. Calculate the pH of the resulting solution.
A. 4.0
B. 5.0
C. 6.0
D. 7.0
Question 5
A 2.0 L sample of a solution containing 0.5 M H₂SO₄ is titrated with 0.5 M NaOH. Calculate the volume of NaOH required to reach the equivalence point.
A. 1.0 L
B. 1.5 L
C. 2.0 L
D. 2.5 L
Question 6
A 2.50-g sample of a metal (M) is dissolved in 25.0 mL of 0.100 M HCl. The resulting solution is then titrated with 0.100 M NaOH. If the volume of NaOH required to reach the equivalence point is 12.5 mL, what is the identity of the metal (M)?
A. Zn
B. Fe
C. Ni
D. Cu
Question 7
The rate cons\tant (k) of a first-order reaction is given by the equation: ln\( [A]t/[A]0 \) = -kt. If the half-life of the reaction is 10 minutes, calculate the rate cons\tant (k) if the initial concentration of the reac\tant is 0.5 M.
A. 0.069 min⁻¹
B. 0.069 hr⁻¹
C. 0.069 s⁻¹
D. 0.069 d⁻¹
Question 8
A 2.00 L flask contains 0.500 atm of N2 and 0.500 atm of O2 at 25°C. What is the total pressure of the gas mixture?
A. 0.500 atm
B. 1.00 atm
C. 1.50 atm
D. 2.00 atm
Question 9
Determine the molar mass of a compound containing 40.0% carbon, 6.7% hydrogen, and 53.3% oxygen by mass. The atomic masses of carbon, hydrogen, and oxygen are 12.01 g/mol, 1.008 g/mol, and 16.00 g/mol, respectively.
A. 120.0 g/mol
B. 150.0 g/mol
C. 180.0 g/mol
D. 200.0 g/mol
Question 10
The solubility of sodium chloride (NaCl) in water is 36 g/100 mL at 25°C. Calculate the molar solubility of NaCl in water at 25°C.
A. 0.1 M
B. 0.2 M
C. 0.3 M
D. 0.4 M
Question 11
Determine the s\tandard electrode potential of the cell represented by the equation: Zn(s) + Cu²⁺(aq) → Zn²⁺(aq) + Cu(s). Given that the s\tandard electrode potential of Zn²⁺/Zn is -0.76 V and that of Cu²⁺/Cu is +0.34 V.
A. +0.10 V
B. -0.10 V
C. +0.50 V
D. -0.50 V
Question 12
Determine the s\tandard Gibbs free energy change (ΔG°) for the reaction: 2Ag+(aq) + 2Cl-(aq) → 2AgCl(s) at 298 K, given the s\tandard Gibbs free energy of formation (ΔGf°) values for Ag+(aq) and Cl-(aq) as 77.1 kJ/mol and -131.2 kJ/mol, respectively.
A. -147.1 kJ/mol
B. 147.1 kJ/mol
C. -147.1 kJ/mol
D. 147.1 kJ/mol
Question 13
A 0.100 M solution of NaOH is titrated with 0.100 M HCl. If the initial volume of NaOH is 25.0 mL and the final volume is 50.0 mL, what is the pH of the resulting solution?
A. 7.00
B. 8.00
C. 9.00
D. 10.0
Question 14
A 0.100 M solution of HCl is titrated with 0.100 M NaOH. If the initial volume of HCl is 25.0 mL and the final volume is 50.0 mL, what is the pH of the resulting solution?
A. 1.00
B. 2.00
C. 3.00
D. 4.00
Question 15
The reaction between sodium (Na) and chlorine (Cl2) produces sodium chloride (NaCl). Write the balanced chemical equation for this reaction.
A. 2Na + Cl2 → 2NaCl
B. Na + Cl2 → NaCl
C. 2NaCl + Cl2 → 2Na
D. Na + NaCl → Cl2

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