The freezing point of heavy water at $1 \ atm$ pressure is: (in $^{\circ}C$)

Zeolite is hydrated sodium aluminium silicate. When treated with hard water,the sodium ions in zeolite are exchanged with

The degree of hardness of water is generally expressed in terms of which of the following?

When the first element of the periodic table is treated with dioxygen,it gives a compound whose solid state floats on its liquid state. This compound has an ability to act as an acid as well as a base. What products will be formed when this compound undergoes autoionisation?

We use polymetaphosphates as water softeners as they:

Why does hard water not form lather with soap?