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Science (086) — AI-generated practice question

AI-generated practice question — model-generated for extra practice, not a previous-year CBSE board question.

Q1. [1] deep exam-ready
Assertion (A): Detergents are more effective than soaps in hard water. Reason (R): Unlike soap molecules, the charged ends of detergent molecules do not form insoluble precipitates with calcium and magnesium ions present in hard water. ((A)) Both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of Assertion (A). ((B)) Both Assertion (A) and Reason (R) are true, but Reason (R) is not the correct explanation of Assertion (A). ((C)) Assertion (A) is true, but Reason (R) is false. ((D)) Assertion (A) is false, but Reason (R) is true.
  1. A Both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of Assertion (A).
  2. B Both Assertion (A) and Reason (R) are true, but Reason (R) is not the correct explanation of Assertion (A).
  3. C Assertion (A) is true, but Reason (R) is false.
  4. D Assertion (A) is false, but Reason (R) is true.
Generated by claude-sonnet-4-6 · 2026-06-26 01:07 · grounding rag
Model Answer

(A) Both Assertion (A) and Reason (R) are true and Reason (R) is the correct explanation of Assertion (A).

Explanation

The textbook states that the charged ends of detergent molecules do not form insoluble precipitates with Ca²⁺ and Mg²⁺ ions in hard water, which is exactly why detergents remain effective in hard water — making R the direct and correct explanation of A.

Previous-year CBSE Grade 10 board exam questions, organised by subject and chapter, each with a model answer — free to read and print.