RRB NTPC · Question 100
An Assertion (A) and a Reason (R) are given below. Assertion (A): Clothes are not washed properly in hard water. Reason (R): Hard water contains many minerals. Choose the correct option. A. A is true but R is false. B. A is false but R is true. C. Both A and R are true and R is the correct explanation of A. D. Both A and R are true but R is not the correct explanation of A.
Show answer & explanation
Answer: (A) D
Explanation
Clothes are not washed well in hard water, and hard water does contain dissolved minerals, so both statements are true. The real reason is that calcium and magnesium salts react with soap to form scum instead of lather; 'contains many minerals' is too general to explain it, so the key marks D.