Question

Permutit is technical name given to

• A. Aluminates of calcium and sodium
• B. Silicates of calcium and sodium
• C. Hydrated silicates of aluminium and sodium
• D. Silicates of calcium and magnesium

Answer 1

Answer: (C)

Hydrated silicates of aluminium and sodium

Answer 2

Permanent hardness is removed by precipitating carbonates of $Ca^{+2}$ and $Mg^{+2}$ $CaCl_2 + Na_2CO_3 \rightarrow CaCO_3 \downarrow + 2NaCl$