Select the correct answers to the questions from the given options. (Do not copy the questions, write the correct answer only.)
Varun’s mother added plenty of salt to the mango pickle she made. This is to: A. enhance the colour of the pickle. B. inhibit the growth of microorganisms. C. increase the nutritional value. D. create a hypertonic solution.
Topic: Osmosis — salt as a preservative
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Pick an option and check your answer. The full worked answer is below either way.
Answer
(d) B and D.
This is a COMBINATION MCQ — the options are pairs, and the answer is the pair B and D. Both are true, and they describe the same event at two levels: D is the mechanism and B is its result.
HOW SALT PRESERVES: a heavy concentration of salt makes the surrounding medium HYPERTONIC, meaning it is more concentrated than the contents of a microbial cell. Water therefore leaves the microbe by OSMOSIS (exosmosis), its protoplasm shrinks away from the cell wall (plasmolysis), and the organism cannot grow or multiply. The pickle keeps.
Why the others are wrong: (A) Salt has no effect on colour. (C) Salt adds no nutritional value; in quantity it is a health concern rather than a benefit.
THE BIOLOGY BEHIND THE KITCHEN: this is the same principle as sugar in jam, and the reason a wilted vegetable sprinkled with salt releases water. Examiners like these everyday examples because they test whether you can apply osmosis outside a textbook diagram.
B and D.