Chemistry 9701 · AS & A Level · Hydroxy compounds

Hydroxy compounds — practice question

Sucrose is a white crystalline solid, $\text{C}_{12}\text{H}_{22}\text{O}_{11}$. In reaction Z, sucrose is combined with water in the presence of the catalyst aqueous hydrochloric acid, forming glucose and fructose.
(a(i))[1]

Suggest a name for the reaction that takes place when sucrose reacts with water to give glucose and fructose.

(a(ii))[3]

If no catalyst is added in reaction Z, the reaction is extremely slow. Label the Boltzmann distribution to show the effect of adding a catalyst to the sample of sucrose and water molecules at constant temperature. Explain your labelled diagram.

(b(i))[1]

Explain what is meant by the term chiral centre.

(b(ii))[1]

On the fructose molecule diagram, mark all the chiral centres with an asterisk (*).

(b(iii))[1]

Determine the empirical formula of fructose.

(c(i))[2]

Explain what is meant by the term enthalpy change of combustion.

(c(ii))[1]

Write the equation for the complete combustion of sucrose.

(c(iii))[2]

Use the data in the table to calculate the enthalpy change for the reaction when sucrose reacts with water, $\Delta H_r$. You should draw a labelled Hess' cycle to present your working.

Worked solution & mark scheme

This 12-mark question has a full step-by-step worked solution and mark scheme. One marking point: hydrolysis

  • Full mark scheme, point by point
  • Step-by-step worked solution
  • Write your answer & get it marked instantly by AI