1. In solvay process, where purified brine is pumped?
a) CO absorber tower
b) H2O absorber tower
c) NH3 absorber tower
d) Carbonation tower
Explanation: In solvay or ammonia-soda process, the purified brine is pumped to the ammonia absorber tower where it dissolves NH3 with liberation of heat. Some CO2 also dissolves in this tower.
2. What is the modification of the dual process?
a) Recovery of NH4Cl as co-product
b) Recovery of NH3 as co-product
c) Recovery of NaHCO3 as co-product
d) Recovery of NH34(NO3) as co-product
Explanation: The principal modification of the dual process is the recovery of NH4Cl as a co-product rather than the liberation of the contained ammonia for recycle as in the solvay process.
3. What is the disadvantage of solvay process?
a) No co-products to dispose
b) Use of low-grade brine
c) Higher salt consumption
d) Low corrosion problems
Explanation: The advantages of solvay process are-can use low-grade brine, less electric power, less corrosion problems, no co-products to dispose while disadvantages are higher salt consumption, more stream consumption etc.
4. Which one is a NaOH process with no Cl2 co-product?
a) HCl-air oxidation with Fe2O3
b) HCl-air-Cl2 oxychlorination
c) HNO3-Nacl-air process
d) Na2CO3– Ca(OH)2
Explanation: Na2CO3-Ca(OH)2 process is the production of NaOH with no Cl2 co-product while HCl-air oxidation with Fe2O3 catalyst, HCl-air-Cl2 oxychlorination process are the production chlorine without any co-products.
5. Where ‘denuding’ is occur_______
a) Diaphragm cell
b) Mercury cell
c) Membrane cell
d) Voltaic cell
Explanation: Denuding reaction occurs in the mercury cell of electrolytic process of chlorine production. In denuding reaction amalgam reacts with water to produce sodium hydroxide, hydrogen and chlorine.
6. Why minor quantities of Na2CO3 required in electrolysis process?
a) For Cl2 drying
b) For high purity brine
c) For salt purification
d) For high purity depleted brine
Explanation: Electrolysis process of chlorine production contains diaphragm cell and mercury cell. In this process,minor quantities of Na2CO3 and NaOH required for the salt purification while H2SO4 is required for Cl2 drying.
7. What are the co-products in the electrolysis of brine?
a) Chlorine and caustic soda
b) Soda ash and caustic soda
c) Soda ash and chlorine
d) Chlorine, caustic soda, and soda ash
Explanation: Co-products produced in the electrolysis of brine are chlorine Cl2 and caustic soda NaOH. 80% of NaOH and >95% of Cl2 are produced in India by this process.
8. Sodium hydroxide is insoluble in water.
a) True
b) False
Explanation: The statement is false since sodium hydroxide is highly soluble in water with high heat of solution (exothermic). It is insoluble in ether and other non-polar solvents.
9. High concentration of NaOH is produced by _____________
a) Mebrane cell process
b) Diaphragm cell process
c) Mercury cell process
d) Chemical process
Explanation: 10-12% NaOH is produced by diaphragm cell which is concentrated to 50%NaOH. 30-33% NaOH is produced by membrane process concentrated to 50% NaOH. 70% NaOH is produced in mercury cell process.
10. Cathode used in electrolysis of brine by diaphragm cell type is _____________
a) Lead
b) Iron
c) Titanium
d) Carbon
Explanation: Iron is used as cathode in electrolysis of brine by diaphragm cell type where H2 gas and aqueous NaOH are obtained. Anode used is graphite where chlorine is obtained.