In a chemical plant a solution of density 1100kg/m3 and specific heat capacity 4.6 kJ/kg-Kis to be heated from 65 OC to 100OC. The required flow rate of the solution is 11.8 kg/s. Atubular heat exchanger is used for this with the solution flowing about 1.2 m/s in 25 mmbore iron tubes and being heated by wet steam at 115OC. The length of the tubes is not toexceed 3.5m . Taking inside, and outside heat transfer coefficient as 5 and 10kW/m2 and neglecting the thermal resistance of the tube wall estimate the number of tubes and the number of tube passes required