General
✓✗At 25 °C, the dissociation constant of a base BOH is 1.0 × 10−12. The concentration of hydroxyl ions in a 0.01 M aqueous solution of the base would be (neglect the ionisation of water)
- 1.0 × 10−7 mol L−1
- 1.0 × 10−6 mol L−1
- 2.0 × 10−6 mol L−1
- 1.0 × 10−5 mol L−1
General
✓✗According to the Lewis concept, an acid is an
- electron-pair donor
- OH− donor
- proton donor
- electron-pair acceptor
General
✓✗The Ksp of AgCl is 1.8 × 10−10 and that of Ag2CrO4 is 1.1 × 10−12. In a solution containing 0.01 M Cl− and 0.01 M CrO42−, Ag+ is added slowly. Which statement is correct?
- Ag2CrO4 precipitates first
- Neither precipitates
- AgCl precipitates first (needs [Ag+] = 1.8 × 10−8 M)
- Both start to precipitate together
General
✓✗Ice and water are in equilibrium at 1 atm. The temperature of this system is
- 298 K
- 0 K
- 273 K
- 373 K
General
✓✗MY and NY3, two nearly insoluble salts, have the same Ksp value of 6.2 × 10−13 at room temperature. Which statement would be true in regard to MY and NY3?
- The molar solubility of MY in water is less than that of NY3.
- The molar solubilities of MY and NY3 in water are identical.
- The salts MY and NY3 are more soluble in 0.5 M KY than in pure water.
- The addition of the salt KY to solutions of MY and NY3 will have no effect on their solubilities.
General
✓✗The molar solubility of PbI2 is 1 × 10−3 mol L−1. Its Ksp is
- 4 × 10−9
- 1 × 10−6
- 2 × 10−6
- 1 × 10−9
General
✓✗For N2(g) + 3H2(g) ⇌ 2NH3(g) at 500 K, Kc = 0.061 L2 mol−2. The value of Kp at the same temperature is about (R = 0.0821 L atm K−1 mol−1)
- 3.62 × 10−5 atm−2
- 102.8 atm−2
- 0.061 atm−2
- 2.50 atm−2
General
✓✗In the reaction HCl + H2O ⇌ H3O+ + Cl−, the conjugate acid−base pairs are
- HCl/H3O+ and H2O/Cl−
- HCl/Cl− and H3O+/H2O
- Cl−/H2O and HCl/H3O+
- HCl/H2O and H3O+/Cl−
General
✓✗For NH4HS(s) ⇌ NH3(g) + H2S(g), Kp = 0.09 atm2. Solid NH4HS is placed in a flask already containing NH3 at 0.5 atm. The partial pressure of H2S at equilibrium is about
- 0.30 atm
- 0.18 atm
- 0.14 atm
- 0.09 atm
General
✓✗For an equilibrium A(g) ⇌ B(g) + C(g), the equilibrium constant Kp is 0.5 atm. If the initial pressure of A is 1 atm (no B or C), the partial pressure of B at equilibrium is
- 0.75 atm
- 0.5 atm
- 0.33 atm
- 0.25 atm
General
✓✗For C(s) + CO2(g) ⇌ 2CO(g), ΔH > 0. The amount of CO at equilibrium increases on
- decreasing temperature and increasing pressure
- increasing temperature and decreasing pressure
- decreasing both temperature and pressure
- increasing both temperature and pressure
General
✓✗Which of the following molecules acts as a Lewis acid?
- (CH3)2O
- (CH3)3B
- (CH3)3N
- (CH3)3P
General
✓✗The correct relation between the dissociation constants of a dibasic acid is
- Ka1 = Ka2
- Ka1 > Ka2
- \( K_{a1} = \dfrac{1}{K_{a2}} \)
- Ka1 < Ka2
General
✓✗The solubility of an M2S-type salt is 3.5 × 10−6 mol L−1. Its solubility product is
- 1.7 × 10−6
- 1.7 × 10−12
- 1.7 × 10−16
- 1.7 × 10−18
General
✓✗The concentrations of H+ and OH− in a 0.1 M aqueous solution of a weak acid that is 2% ionised are (Kw = 1 × 10−14)
- 2 × 10−3 M and 5 × 10−12 M
- 1 × 10−3 M and 3 × 10−11 M
- 3 × 10−2 M and 4 × 10−13 M
- 0.02 × 10−3 M and 5 × 10−11 M