Chemistry
(a) Neeraj observed that the stain of curry on a white shirt becomes reddish brown when baking soda is scrubbed on it, but it turns yellow again when the shirt is washed with plenty of water. What might be the reason for his observation?
(b) Write the equation for the preparation of ethanoic acid from ethanol.
Practical Chemistry
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Answer
(a) The curry stain is yellow due to presence of turmeric in it. Turmeric is a natural indicator and is sensitive to changes in pH value. Baking soda is a basic substance hence when it is scrubbed on the curry stain, the turmeric changes to reddish brown colour. On washing, the water rinsed away the baking soda as well as the top layer of turmeric that changed colour. So the stain turned yellow again.
(b) Ethanoic acid from ethanol
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