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प्रश्न
Do all the fruits and vegetables undergo browning? Explain.
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उत्तर
No, not all the fruits. Enzymic browning can be observed in fruits such as apricots, pears, bananas, grapes, and avocados and vegetables such as aubergines, potatoes, lettuce. The enzyme polyphenol oxidase or tyrosinase that when in contact with oxygen catalyzes a biochemical reaction of plants phenolic compounds to brown pigments known as melanin, which results in the fruit or vegetable turning brown.
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संबंधित प्रश्न
A chemical reaction is a temporary reaction.
Match the following.
| Spoilage | Decomposition |
| Ozone | Biocatalyst |
| Tarnishing | Oxygen |
| Yeast | Chemical reaction |
| Calcium oxide | Food |
What happens when an iron nail is placed in copper sulphate solution?
Explain how food items are spoiled by chemical reactions?
Burning of fossil fuels is responsible for global warming. Justify the statement.
Classify the following day-to-day activities based on chemical reactions by physical contact, solutions of reactants, heat, light, electricity, and catalyst.
- Burning of crackers during festivals
- Fading of coloured clothes on drying under sunlight.
- Cooking of eggs.
- Charging of batteries.
Kumar is going to build a house. To purchase the iron rods required for construction, he visited an iron and steel shop nearby. The seller showed him some iron rods which are fresh and good. He also showed him little older iron rods which are brownish in appearance. The price of fresh rods is more than the older ones. The seller also gave some offers to older ones. Kumar’s friend Ramesh advised him not to buy the cheaper rods.
- Is Ramesh right in his suggestion?
- Could you explain the reason for his suggestion?
- What are the values shown by Ramesh?
Explain the environmental effects of chemical reactions?
Reason out
Ozone is produced naturally in the stratosphere.
An element ‘A’ on exposure to moist air turns reddish-brown and a new compound ‘B’ is formed. The substance ‘A’ and ‘B’ are:
