Commercial packed scrubbers are normally designed for a pressure drop range of ________ mm water column per metre of packed height?

Chromite refractories are used in________?

Milk is dried usually in a ________ dryer?

Tin coating on metals is not done by________?

Viscosity of water at 40°C lies in the range of________?

Which of the following processes can remove both temporary as well as permanent hardness of water?