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Food test procedures incomplete or wrong
“Benedict's test was often incomplete as it was common for the heating step to be left out.”— Paper 4, May/June 2025
How to fix: Memorise all food tests: Benedict's (add reagent + HEAT in water bath → orange/red for reducing sugar). Biuret (add NaOH then CuSO₄ → purple for protein). Iodine solution (→ blue-black for starch). Ethanol emulsion test (dissolve in ethanol, add to water → white emulsion for fats). DCPIP (decolourises with vitamin C).