AIIMS2003Chemistry-Solutions
AIIMS 2003 Chemistry Water Hardness MCQ Question
Type: MCQ-conceptual-Medium-Class 12
The reagent commonly used to determine hardness of water titrimetrically is
A
oxalic acid
B
disodium salt of EDTA
C
sodium citrate
D
sodium thiosulphate
Correct Answer
Option B
Detailed Explanation
Disodium salt of ethylene diamine tetraacetic acid has been used for the estimation of M2+ metal ions like Mg2+, Ca2+ etc. by complexometric titrations. In this titration, indicator ions (D2- ions) form red-metal indicator complex, [MD-] with M2+ ions.
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