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Class 12 Chemistry Chapter 1: Solutions Assertion-reason questions with answers

2 assertion-reason questions on Solutions, each with its answer and the reason, written from the NCERT chapter. For the CBSE board, JEE Main and NEET, which are set from the same NCERT chapter. Open a question's solution to check your working; then take the free test to find your next chapter. Each question gives an Assertion (A) and a Reason (R); choose how they stand to each other.

Question 1
Assertion (A): The amount of oxygen dissolved in a pond falls on a hot afternoon. Reason (R): Dissolution of a gas in a liquid is an exothermic process.
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Answer: (a) Both A and R are true, and R is the correct explanation of A.

Dissolving a gas evolves heat, like condensation; by Le Chatelier's principle a rise in temperature shifts the equilibrium back, so solubility falls. R explains A.

Question 2
Assertion (A): Bottles of soda water are sealed under high pressure. Reason (R): The Henry's law constant of a gas increases with temperature.
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Answer: (b) Both A and R are true, but R is not the correct explanation of A.

Both are true. Sealing under high pressure raises the solubility of CO₂ because solubility is proportional to partial pressure (Henry's law); the rise of KH with temperature does not explain the sealing.

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