Cisplatin, [Pt(NH₃)₂Cl₂], is used as an anti-cancer drug - AQA - A-Level Chemistry - Question 4 - 2020 - Paper 3

The equation for the formation of the complex ion B when cisplatin reacts with water can be represented as:

$[Pt(NH₃)₂Cl₂] + H₂O \rightarrow [Pt(NH₃)₂(H₂O)]^{+} + Cl^{-}$

In Figure 1, illustrate the cross-link by drawing a bond between the platinum ion from ion B and the nitrogen atoms in the two adjacent guanine nucleotides. Indicate the two connections indicating how the platinum forms a bridge between these nucleotides.

To confirm that the reaction is first order, the concentration of cisplatin can be plotted against time. If the resulting graph is a straight line when the natural logarithm of the concentration is plotted against time, it indicates a first-order reaction. Additionally, the slope of this graph will correspond to the negative rate constant of the reaction.

Fill in the missing values in Table 1 based on the provided calculations, ensuring that the values for ( \frac{1}{T} ) and ( \ln k ) are accurate.

Using the Arrhenius equation and the plotted graph, calculate the activation energy. The gradient of the line in the Arrhenius plot provides (-Eₐ/R). Given the gradient from the graph, the activation energy can be derived as:

$Eₐ = -\text{Gradient} \times R$

Given that the gas constant R is 8.31 J K⁻¹ mol⁻¹, convert the final value to kJ/mol for the answer.