Quelpr
1 markAcid/Base Equilibria

CAPE Chemistry Unit 1 · May/June 2026 · Paper 2 · Question 2(d)(ii)

Dissociation constant of hydrofluoric acid, HF, is 5.62 * 10^-4 mol dm^-3.

Write the expression for the dissociation constant for hydrofluoric acid.

The mark scheme is shown once you've answered.

Practise this question

Other parts of this question

  1. 2(a)Define the term 'rate of a reaction'.[2 marks]
  2. 2(b)(i)With reference to the experiment number used, deduce the order of the reaction with respect to Substance A and Substance B.[4 marks]
  3. 2(b)(ii)Write the rate equation for the reaction between A and B.[1 mark]
  4. 2(b)(iii)Using the rate equation from (b)(ii), calculate the numerical value of the rate constant k, stating its unit.[2 marks]
  5. 2(b)(iv)Using the rate equation from (b)(ii), suggest a mechanism for the reaction between A and B.[2 marks]
  6. 2(c)Define the term 'acid' using the Bronsted-Lowry theory.[1 mark]
  7. 2(d)(i)Write the equation for the dissociation of hydrofluoric acid in aqueous solution.[2 marks]
  8. 2(d)(iii)Calculate the pH of 0.10 mol dm^-3 hydrofluoric acid.[3 marks]
  9. 2(d)(iv)A student performs a titration, adding 0.10 mol dm^-3 sulfuric acid to 25 cm³ of 0.10 mol dm^-3 sodium hydroxide solution. Using the axes in Figure 1, sketch a…[3 marks]
  10. 2(e)(i)Define standard cell potential.[2 marks]
  11. 2(e)(ii)Define standard electrode potential.[2 marks]
  12. 2(f)Describe, in detail, the steps that could be used to determine the standard electrode potential of copper in the laboratory.[5 marks]

More practice: the rest of this paper · more Acid/Base Equilibria questions · all CAPE Chemistry Unit 1 past papers