A food analyst investigated a synthetic orange food colouring using paper chromatography.
a.[1]
The orange food colouring contains 64% Sunset Yellow FCF dye and 36% Ponceau 4R dye by mass. Determine the simplest whole-number ratio of Sunset Yellow FCF dye : Ponceau 4R dye in this colouring.
b.[2]
In the paper chromatogram, the analyst recorded the measurements shown in the diagram below.
Calculate the RfR_{\text{f}}Rf value of the Sunset Yellow FCF dye (the upper spot) using the equation:
Rf=distance moved by dyedistance moved by solvent front R_{\text{f}} = \frac{\text{distance moved by dye}}{\text{distance moved by solvent front}} Rf=distance moved by solvent frontdistance moved by dyec.[1]
Under the same experimental conditions, if the analyst tested a different batch of orange food colouring containing 45% Sunset Yellow FCF dye and 55% Ponceau 4R dye, state what would happen to the RfR_{\text{f}}Rf value of the Sunset Yellow FCF dye.