The ion product constant of water, Kw, is defined by which expression?
A. Kw = [H₂O]
B) Kw = [H⁺] + [OH⁻]
C) Kw = [H⁺][OH⁻]
D) Kw = [H⁺]/[OH⁻]
For a weak acid HA undergoing dissociation: HA ⇌ H⁺ + A⁻, what is the expression for Ka?
A) Ka = [HA]/([H⁺][A⁻])
B) Ka = [H⁺][A⁻]
C) Ka = [H⁺][A⁻]/[HA]
D) Ka = -log₁₀[H⁺]
What is the pH of a 0.25 mol dm⁻³ HCl(aq) solution?
A) 0.25
B) 0.60
C) 1.00
D) 1.40
What is the pH of a 0.0500 mol dm⁻³ sodium hydroxide solution? (Kw = 1.00 × 10⁻¹⁴ mol² dm⁻⁶)
A) 1.30
B) 12.0
C) 12.3
D) 12.7
In the following reaction in an organic solvent:HCl + HI ⇌ H₂Cl⁺ + I⁻Which statement is correct?
A) HCl is the acid and HI is the base.
B) HI is the acid and HCl is the base.
C) HCl is the acid and I⁻ is the base.
D) HI is the acid and H₂Cl⁺ is the base.
Considering the same reaction: HCl + HI ⇌ H₂Cl⁺ + I⁻, which of the following correctly identifies the conjugate acid-base pairs?
A) H₂Cl⁺ is the conjugate base of HCl, and I⁻ is the conjugate acid of HI
B) H₂Cl⁺ is the conjugate acid of HI, and I⁻ is the conjugate base of HCl
C) H₂Cl⁺ is the conjugate base of HI, and I⁻ is the conjugate acid of HCl
D) H₂Cl⁺ is the conjugate acid of HCl, and I⁻ is the conjugate base of HI
A 0.0500 mol dm⁻³ solution of the weak acid propanoic acid has a pH of 3.1. Which of the following values is closest to the Ka for propanoic acid?
A) 1.0 × 10⁻³
B) 5.0 × 10⁻⁴
C）1.3 × 10⁻⁵
D) 2.0 × 10⁻⁶
Given Ksp for CuBr is 3.2 × 10⁻⁸ mol² dm⁻⁶, what is its solubility in pure water (mol dm⁻³)?
A) 1.6 × 10⁻⁴
B) 1.8 × 10⁻⁴
C) 3.2 × 10⁻⁸
D) 5.7 × 10⁻³
Given Ksp for CuBr is 3.2 × 10⁻⁸ mol² dm⁻⁶, what is the approximate solubility of CuBr in 0.0100 mol dm⁻³ NaBr solution?
A) 1.8 × 10⁻⁴
B) 3.2 × 10⁻⁶
C) 3.2 × 10⁻⁸
D) 5.7 × 10⁻³
Why does CuBr solubility differ in pure water vs NaBr solution?
A) NaBr reacts chemically with CuBr.
B) Br⁻ ions from NaBr shift the equilibrium left (common ion effect).
C) Na⁺ ions complex with Cu⁺ ions.
D) Ionic strength decreases ion concentration.
In a paper chromatography experiment, the disatnce travelled by solvent is 12.0 cm and 8.4 cm for the solute. What is the Rf value of the solute?
A) 0.42
B) 0.70
C) 1.43
D) 3.60
A component with a high Rf value in paper chromatography is:
A) Highly soluble in the stationary phase.
B) Highly soluble in the mobile phase.
C) A very small molecule.
D) The same color as the solvent.