Dietary vitamin $$\(\mathrm{C}\)$$ is an antioxidant that may be linked to the risk of cardiovascular disease (CVD). The vitamin C content of food and drink can be measured using DCPIP. The concentration of vitamin $$\(\mathrm{C}\)$$ in a solution can be determined by finding the volume of the solution that causes DCPIP to change colour. The higher the concentration of vitamin $$\(\mathrm{C}\)$$ in the solution, the smaller the volume needed to cause the colour change. (i) Explain what happens to DCPIP in the presence of vitamin C. (2) (ii) In an investigation, a student compared the vitamin C concentration of freshly squeezed fruit juice and fruit juice stored in a carton. The table shows the results of this investigation. The standard solution contained $$\(10 \mathrm{mg}\)$$ of vitamin $$\(\mathrm{C}\)$$ per $$\(\mathrm{cm}^{3}\)$$. $$\(1.5 \mathrm{~cm}^{3}\)$$ of this standard solution decolourised $$\(1 \mathrm{~cm}^{3}\)$$ of $$\(1 \%\)$$ DCPIP. Calculate the concentration of vitamin C in carton lemon juice. (2) Answer $$\(\mathrm{mg} \mathrm{cm}^{-3}\)$$ (iii) Calculate the concentration of vitamin $$\(\mathrm{C}\)$$ in lime juice from a carton as a percentage of fresh lime juice. (2) Answer $$\(\%\)$$ (iv) The results in the table were plotted as a bar chart. Complete the bar chart by labelling the axes and showing the standard deviation for fresh orange juice and for orange juice from a carton. (2) (v) Comment on the vitamin C content of fresh juice compared with juice from a carton. (3)

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