Which of the following is the most detrimental for water used in high pressure boiler ?

Related Mcqs:

1. The detrimental effect on organism and water quality with temperature rise of aquatic system is the reduction of _____________ of water?

   A. Dissolved oxygen content
   B. Biological oxygen demand
   C. Vapor pressure
   D. All A., B. and C.

2. Pick out the wrong statement. A. Caustic embrittlement of boiler’s metallic parts is caused by high concentration of caustic soda in boiler feed water___________________?

   B. Cooling and freezing of water kills the bacteria present in it
   C. With increasing boiler operating pressure of steam, the maximum allowable concentration of
   silica in feed water goes on decreasing
   D. Dissolved oxygen content in high pressure boiler feed water should be nil

3. Deaeration of high pressure boiler feed water is done to reduce ___________________?

   A. Foaming from boilers
   B. Its dissolved oxygen content
   C. Its silica content
   D. Caustic embrittlement

4. The vapour pressure of water is given by, in Psat = A – (5000/T), where A is a constant, Psat is the vapour pressure in atm. and T is the temperature in K. The vapor pressure of water in atm. at 50°C is approximately__________________?

   A. 0.07
   B. 0.09
   C. 0.11
   D. 0.13

5. Saturated solution of benzene in water is in equilibrium with a mixture of air and vapours of benzene and water at room temperature and pressure. Mole fraction of benzene in liquid is xB and the vapour pressures of benzene and water at these conditions are pv B and pv w respectively. The partial pressure of benzene in air-vapour mixture is_________________?

   A. PvB
   B. xB.PvB
   C. (Patm – Pvw)xB
   D. xB.Patm

6. For water at 300°C, it has a vapour pressure 8592.7 kPa and fugacity 6738.9 kPa Under these conditions, one mole of water in liquid phase has a volume of 25.28 cm3 and that in vapour phase in 391.1 cm3.Fugacity of water (in kPa) at 9000 kPa will be__________________?

   A. 6738.9
   B. 6753.5
   C. 7058.3
   D. 9000

7. Soluble silica present in boiler feed water can be removed by______________________?

   A. Coagulation
   B. Filtration
   C. Anion exchanger
   D. Preheating it

8. Foaming and priming in boiler operation can be reduced by reduction in ______________ in feed water?

   A. Turbidity
   B. Color (Hazen)
   C. Total solids
   D. All A., B. & C.

9. Tri-sodium phosphate is used in boiler water treatment to reduce____________________?

   A. Turbidity
   B. Caustic embrittlement
   C. Suspended silica
   D. Dissolved oxygen

10. Consider the equilibrium A(g) + B(g) = AB(g). When the partial pressure of A is 10-2 atm, the partial pressure of B is 10-3 atm and the partial pressure of AB is 1 atm, the equilibrium constant ‘K’ is____________________?

    A. 10 atm-1
    B. 105 atm-1
    C. 10 (dimensionless)
    D. 105 (dimensionless)