A water sample contains 97.2 mg/L of Ca(HCO3)2 (molar mass 162) and 60 mg/L of MgSO4 (molar mass 120). Hardness is expressed as ppm of CaCO3 (molar mass 100). The permanent hardness is

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JEE Main levelSingle correct optionDifficulty 2 of 3eq096

A water sample contains $97.2 mg/L$ of $Ca (HCO X_{3}) X_{2}$ (molar mass $162$ ) and $60 mg/L$ of $MgSO X_{4}$ (molar mass $120$ ). Hardness is expressed as ppm of $CaCO X_{3}$ (molar mass $100$ ). The permanent hardness is

A81 ppm
B110 ppm
C60 ppm
D50 ppm

Answer: D

Ca(HCO3)2 = 97.2/162 = 0.60 mmol/L (temporary hardness = 60 ppm). MgSO4 = 60/120 = 0.50 mmol/L, which is not removed by boiling, so permanent hardness = 0.50 x 100 = 50 ppm (total 110 ppm).

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A water sample contains 97.2 mg/L of Ca(HCOX3​)X2​ (molar mass 162) and 60 mg/L of MgSOX4​ (molar mass 120). Hardness is expressed as ppm of CaCOX3​ (molar mass 100). The permanent hardness is

Answer: D

More questions on Back titration and hardness of water

A water sample contains $97.2 mg/L$ of $Ca (HCO X_{3}) X_{2}$ (molar mass $162$ ) and $60 mg/L$ of $MgSO X_{4}$ (molar mass $120$ ). Hardness is expressed as ppm of $CaCO X_{3}$ (molar mass $100$ ). The permanent hardness is