Problem-3: 0.45 gm of CaCO3 was dissolved in HCI and the solution made up to 500 mL with distilled water. 50 mL of the resulting solution required 50 ml of EDTA solution for titration when titarted using EBT indicator. 50 mL of hard water sample required 18 mL of EDTA. After boiling and filtering 50 mL water from the same source required 10 mL of EDTA solution. Calculate each type of hardness of water in CaCO3 equivalents in ppm.

Electron equations of the given changes are as follow,a)                              cu      →      cu⁺²  + 2e⁻b)                              mg⁺²  +  2 e⁻      →      mgc)                              cl⁻    →      cl  +  1e⁻d)                              s  +  2 e⁻    →      s²⁻e)                                o²⁻      →      o  +  2 e⁻f)                              p  +  3 e⁻    →      p³⁻g)                              fe²⁺    →      fe³⁺  + 1 e⁻h)                              s²⁻    →      s⁴⁺  +  6 e⁻

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