3. A double-effect evaporator is used to concentrate 1500lb/hr of 10%NaOH solution with the feed temperature 140F. The following bar chart shows the temperature in two effects: The overall heat transfer coefficients for the first and second effect are 250 , and 100BBu2ft2hF, respectively. The specific heat Cp for the saturated steam is 0.45Btu/lb.F. a. Find the mass fraction of the concentrate and pressure in the vapor space for the first and second effect (8%) b. What are the heat transfer areas required in the first and second effect? (6%) c. What is the amount of steam required for the double-effect evaporator? (3\%) (d. If we remove the second effect and use double amount of the steam with the same temperature, will the mass fraction of the final concentrate be larger compared to that using double-effect evaporator? Why or why not? (10%)