RRB NTPC Prelims Model Paper 5 with solutions

(1) The water into which carbon-dioxide gas has been dissolved under pressure, is called soda water. The process of dissolving carbon dioxide in water is called carbonation.Commercial soda water in siphons is made by chilling filtered plain water to 8 degree C (46 degree F) or below, optionally adding a sodium or potassium based alkaline compound such as sodium bio carbonate to reduce acidity,and then pressurizing the water with carbon dioxide.