Chemistry (Part-III) (Railway)

21. Ionization constant of Nitrous Oxide (HNO₂) is: [RRB RPF/RPSF SI Exam, 10.01.2019 Shift-III]

(1) 2.8×10⁻⁴
(2) 4.5×10⁻⁴
(3) 3.8×10⁻⁴
(4) 1.5×10⁻⁴

Correct Answer: (2) 4.5×10⁻⁴

Solution:An ionization constant (using the symbol K) is a constant that depends upon the equilibrium between ions and molecules that are not ionized in a solution or liquid. It is the ratio of products and reactants raised to appropriate stoichiometric powers or the ratio between the product of concentration and reactant. The ionization constant of nitrous acid is 4.5 x 10⁻⁴.

22. Generally _________ carries minerals from leaves to other parts of plants [RRB RPF/RPSF SI Exam, 10.01.2019 shift- III]

(1) Trachelds
(2) Xywlem
(3) Phloem
(4) Vessel

Correct Answer: (3) Phloem

Solution:Xylem tissue is used mostly for transporting water from roots to stems and leaves but also transports other dissolved compounds. Phloem is responsible for transporting food produced from photosynthesis from leaves to non-photosynthesizing parts of a plant such as roots and stems.

23. Which of the following make the solution colourless by absorbing the impurities of colour ? [RRB RPF/RPSF SI Exam, 11.01.2019 Shift-II]

(1) Aluminimum
(2) Hydrogen
(3) Potassium Chloride
(4) Animal Charcol

Correct Answer: (4) Animal Charcol

Solution:Adsorption is the phenomenon of attracting and retaining the molecules of a substance on the surface of a liquid or solid resulting into a higher concentration of molecules on the surface. The substance adsorbed on the surface is called adsorbate and the substance on which it is adsorbed is called adsorbent. Animal charcoal is used to remove colouring matter from sugarcane juice in the manufacture of sugar.

24. With which of the following Acid Phenol get oxidised for the formation of Benzoquinones [RRB RPF/RPSF SI Exam, 11.01.2019 Shift-III]

(1) Carboxilic Acid
(2) Chromic Acid
(3) Benzoic Acid
(4) Sulphuric Acid

Correct Answer: (2) Chromic Acid

Solution:The term chromic acid is usually used for a mixture made by adding concentrated sulfuric acid to a dichromate, which may contain a variety of compounds, including solid chromium trioxide. This kind of chromic acid may be used as a cleaning mixture for glass.

25. In which of the following group of element property of metal and non-metal both found? [RRB RPF/RPSF SI Exam, 11.01.2019 Shift-III]

(1) Collide
(2) Metalloid
(3) Gluon
(4) Axion

Correct Answer: (2) Metalloid

Solution:A metalloid is an element that has properties that are intermediate between those of metals and nonmetals. Metalloids fall between metals and nonmetals in the periodic table. They also fall between metals and nonmetals in terms of their properties.

26. What is the mixture of copper and silver used by the Satavahanas called? [RRB RPF/RPSF SI Exam, 12.01.2019 Shift-II]

(1) Tanka
(2) Jeetal
(3) Potin
(4) Nishk

Correct Answer: (3) Potin

Solution:The Sataavahana coins are made up of Copper, Silver, Lead and Potin in different shapes such as Round. Square and Rectangular. Silver coins are commonly seen after Gautami-putra Satakarni, majority of which depict the portraits of Kings. Potin is a base metal silver-like alloy used in coins.

27. Whcih among the following is known as the Fruit Spirit? [RRB RPF/RPSF SI Exam, 12.01.2019 Shift-III]

(1) ethanol
(2) phenol
(3) methanol
(4) butanol

Correct Answer: (3) methanol

Solution:Methanol may also be called, wood alcohol or wood spirit because it can be produced as a by-product of the wood distillation.

28. The process of obtaining ammonia by reacting hydrogen with nitrogen is called? [RRB RPF/RPSF SI Exam, 13.01.2019 Shift-II]

(1) Haber method
(2) Calgon's method
(3) Exothermic method
(4) Endothermic method

Correct Answer: (1) Haber method

Solution:The Haber process is a common process used to manufacture ammonia from hydrogen and nitrogen. Nitrogen is obtained from the air, while hydrogen is obtained from natural gas. Ammonia is used to manufacture chemicals, plastics, pesticides, and more.

29. Which one of the following is a natural source of citric acid? [RRB RPF/RPSF SI Exam, 13.01.2019 Shift-III]

(1) Potato
(2) Tamarind
(3) Lemon
(4) Milk

Correct Answer: (3) Lemon

Solution:Citric acid is a weak organic acid that has the chemical formula C₆H₈O₇. Citric acid is found naturally in citrus fruits, especially lemons and limes.

30. What is the atomic number of Beryllium?

(1) 3
(2) 1
(3) 4
(4) 2

Correct Answer: (3) 4

Solution:Beryllium is a chemical element with the symbol Be and atomic number 4. It is a relatively rare element in the universe, usually occurring as a product of the spallation of larger atomic nuclei that have collided with cosmic rays. Within the cores of stars, beryllium is depleted as it is fused into heavier elements.