NON-MEATALS, B. Hydrogen and its Compounds

21. Water can dissolve more substances than any other liquid because — [I.A.S. (Pre) 2021]

(a) It is dipolar in nature
(b) It is a good conductor of heat
(c) It has a high value of specific heat
(d) It is an oxide of hydrogen

Correct Answer: (a) It is dipolar in nature

Solution:

Water is often called the "universal solvent" due to its dipolar (polar) nature. The oxygen atom in water has a slight negative charge, and the hydrogen atoms have slight positive charges. This polarity allows water molecules to interact strongly with other polar molecules and with ions, effectively dissolving them. The principle "like dissolves like" applies here: polar water dissolves other polar and ionic substances.

22. Large quantities of drinking water are prepared from impure water by — [Uttarakhand P.C.S. (Pre) 2005]

(a) Desalination
(b) Distillation
(c) Ion-exchange
(d) Decantation

Correct Answer: (a) Desalination

Solution:Desalination is a process that removes mineral components from saline water (also refer to removal of salts and minerals). Saltwater is desalinated to produce water suitable for human consumption or irrigation. Seawater desalination is a very effective way of production of potable water for drinking. irrigation and industries.

23. Which gas is used in the purification of drinking water? [Jharkhand P.C.S. (Pre) 2013]

(a) Helium
(b) Chlorine
(c) Fluorine
(d) Carbon dioxide

Correct Answer: (b) Chlorine

Solution:Chlorine is presently an important chemical for water purification (such as in water treatment plants), as disinfectants and in bleach. Chlorine is usually used to kill bacteria and other microbes in drinking water supplies and public swimming pools.

24. By which process can sea water be converted into pure water? [R.A.S./R.T.S. (Pre) 2008]

(a) Deliquescence
(b) Efflorescence
(c) Electric separation
(d) Reverse osmosis

Correct Answer: (d) Reverse osmosis

Solution:Reverse osmosis (RO) is a water purification technology that uses a semipermeable membrane to remove larger particles from drinking water. It is used in desalination of sea water or salty water. The most widely used method of desalination on a large scale involves reverse osmosis. If pure water and salty water are placed on both sides of a semipermeable membrane, water will flow towards the salty water side. If a high pressure (higher than the osmotic pressure) is applied to the salty water side of the semi- permeable membrane, the water will flow in the opposite direction and pure water will be obtained. Reverse osmosis can remove many types of molecules and ions from solutions including bacteria and is used in both industrial processes and the production of potable pure water.

25. The process used for transforming salty water into pure water is called — [U.P.P.C.S. (Mains) 2013]

(a) Deliquescence
(b) Efflorescence
(c) Electric separation
(d) Reverse osmosis

Correct Answer: (d) Reverse osmosis

Solution:Reverse osmosis (RO) is a water purification technology that uses a semipermeable membrane to remove larger particles from drinking water. It is used in desalination of sea water or salty water. The most widely used method of desalination on a large scale involves reverse osmosis. If pure water and salty water are placed on both sides of a semipermeable membrane, water will flow towards the salty water side. If a high pressure (higher than the osmotic pressure) is applied to the salty water side of the semi- permeable membrane, the water will flow in the opposite direction and pure water will be obtained. Reverse osmosis can remove many types of molecules and ions from solutions including bacteria and is used in both industrial processes and the production of potable pure water.

26. By which process does Alum clean muddy water? [R.A.S./R.T.S. (Pre) 2000]

(a) Absorption
(b) Adsorption
(c) Coagulation
(d) Dialysis

Correct Answer: (c) Coagulation

Solution:Alum (aluminium sulphate) is added to the water to destabilize natural fine particulate matter suspended in the water. This process is known as coagulation. The impurities found in water suspensions consists of charged colloids ranging in size from 5mm to l mm and particles greater than 0.5 mm. The addition of alum causes these particles to collide and clump together to form heavy cluster which will settle in water.

27. The gas used in the manufacture of Vanaspati Ghee from Vanaspati Oil is — [60th to 62nd B.P.S.C. (Pre) 2016, U.P.P.C.S. (Mains) 2013]

(a) Hydrogen
(b) Oxygen
(c) Nitrogen
(d) Carbon dioxide

Correct Answer: (a) Hydrogen

Solution:Hydrogen gas is used in the manufacturing of vanaspati ghee. To prepare vanaspati ghee, hydrogen gas is passed through vegetable oils under 8-10 atmospheric pressure in the presence of nickel powder (which works as a catalyst) at a temperature of 150-180°C. The oil changes into vegetable ghee or solid fat known as vanaspati ghee. This process is called hydrogenation. Hydrogenation is a process in which unsaturated compounds combine with hydrogen in the presence of a catalyst, under suitable conditions, and are converted into saturated compounds.

28. Which one of the following catalysts is used in hydrogenation of vegetable oils? [U.P. P.C.S. (Mains) 2016]

(a) Zinc
(b) Platinum
(c) Nickel
(d) Iron

Correct Answer: (c) Nickel

Solution:Hydrogen gas is used in the manufacturing of vanaspati ghee. To prepare vanaspati ghee, hydrogen gas is passed through vegetable oils under 8-10 atmospheric pressure in the presence of nickel powder (which works as a catalyst) at a temperature of 150-180°C. The oil changes into vegetable ghee or solid fat known as vanaspati ghee. This process is called hydrogenation. Hydrogenation is a process in which unsaturated compounds combine with hydrogen in the presence of a catalyst, under suitable conditions, and are converted into saturated compounds.