Permutit is:

1. hydrated sodium aluminium silicate

2. sodium hexa meta-phosphate

3. sodium silicate

4. sodium meta-aluminate

Which is used to determine hardness of water volumetrically ?

1. H₂C₂O₄

2. Na₂S₂O₃

3.Sod. citrate

4. Di sodium salt of EDTA

Both temporary and permanent hardness are removed on boiling water with:

1. Ca(OH)₂

2. Na₂CO₃

3. CaCO₃

4. CaO

When zeolites (hydrated sodium aluminum silicate) is treated with hard water, the sodium ions are exchanged with:

1. H⁺ ion

2. Ca²⁺ ion

3. ${\mathrm{SO}}_4^{2-}$ ion

4. OH^- ion

Temporary hardness is caused due to the presence of:

1. CaSO₄

2. CaCl₂

3. CaCO₃

4. Ca(HCO₃)₂