Water MID I model objective question

     The disinfection action of bleaching powder is  due to                                           

                

• A)   HOCl (hypochlorous acid )

• B) HCl

• C) Ca(OH)₂

•      D) CaCl₂  

Answer explanation

The disinfection action of bleaching powder is primarily due to HOCl (hypochlorous acid), which is a strong oxidizing agent effective in killing bacteria and viruses, making option A the correct choice.

3. Cation exchange resin is regenerated by

                                     

• A)                NaOH

• B)        HCl

• C)        NaCl

• D) KOH

Answer explanation

Cation exchange resins are regenerated using acids. HCl (hydrochloric acid) effectively replaces the cations on the resin with H+ ions, making it the correct choice for regeneration.

How many binding sites are available on EDTA                                                

                              

• A)   3

• B)     4

• C)  6

• D) 5

Answer explanation

EDTA (ethylenediaminetetraacetic acid) has six binding sites that can chelate metal ions, making the correct answer C) 6. This property is crucial for its use in various chemical and biological applications.

   The permanent hardness of water is due to                                                                   

                       

•   HCO₃^-

• CO₃^- 

• Cl^-

• Na⁺

Answer explanation

The permanent hardness of water is primarily caused by the presence of dissolved salts, particularly chlorides like Cl-. Unlike bicarbonates, which can be removed by boiling, chlorides remain in solution, contributing to permanent hardness.

                       functional groups are present in anion exchange resin membranes

Answer explanation

Anion exchange resin membranes contain functional groups that are typically acidic, allowing them to attract and exchange anions. Therefore, the correct answer is 'Acidic'.

The hardness of water is expressed in terms of _________________________

equivalence.

Answer explanation

The hardness of water is commonly expressed in terms of calcium carbonate (CaCO3) equivalence, which quantifies the concentration of hardness-causing minerals in water.

___________________ salt is responsible for caustic embrittlement.

Answer explanation

Na2CO3, or sodium carbonate, is known to cause caustic embrittlement in metals, particularly in high-temperature water systems. This occurs due to its ability to increase the pH and lead to stress corrosion cracking.

                             type of phosphate salt is used to treat acidic water

Answer explanation

Na2HPO4, or disodium hydrogen phosphate, is commonly used to treat acidic water due to its ability to neutralize acidity and maintain pH balance, making it the correct choice for this application.

  Which method is not used for the disinfection of water                                                         

             

• A)   Electrodialysis

• B) Ozonization

• C) Chlorination

• D) Chloramines

Answer explanation

Electrodialysis is primarily used for desalination and ion removal, not for disinfection. In contrast, ozonization, chlorination, and chloramines are established methods for disinfecting water.

Caustic embrittlement caused by the presence of                                                                   

                       

• A) NaCl

• B) NaOH

• C) MgCO3

• D) KNO3

Answer explanation

Caustic embrittlement occurs due to the presence of NaOH (sodium hydroxide), which can lead to the weakening of steel. Other options like NaCl, MgCO3, and KNO3 do not cause this effect.