Wbcs previous year Solve .Best book for wbcs

Friday, 19 October 2018

10 questions from Chemistry

1) Which among the following was first human-made plastic?
 [A] Bakelite [B] Polyethene [C] Celluloid [D] Nylon

2) Amalgam’ is a term used for an alloy of a metal with : 
[A] Copper [B] Mercury [C] Lead [D] Aluminium

3) The Potassium graphite and Calcium Graphite can be mostly used as which among the following? 
[A] Moderators [B] Semiconductors [C] Superconductors [D] Lubricants 

4) The colors in the fine cut diamond are because of which among the following? 
[A] Variance in transparency of diamond [B] Variance in index of refracti [C] Presence of Impurities [D] Existence of definite planer layers

5) Acetylene cannot be safely pressurized as a pure compound. Which among the following is used for safe storage and transportation of Acetylene? [A] Kerosene [B] Acetone [C] Vinegar (Acetic Acid) [D] Propylene glycol

6) Which among the following substances is being used most commonly for producing synthetic jet Fuel? [A] Coal [B] Natural Gas [C] Plastic Waste [D] Biom

7) Pyrolusite, Braunite, Psilomelane and Rhodochrosite are the ores of which among the following:  1. Manganese  2. Aluminium  3. Copper  Choose the correct option: [A] Only 1 [B] Only 1 & 2 [C] Only 3 [D] Only 1 & 3

8) For respiration in deep sea, divers use mixture of: [A] Oxygen and helium [B] Oxygen and hydrogen [C] Oxygen and carbon dioxide [D] Oxygen, Helium

9) The minimum temperature at which a combustible substance catches fire is called: [A] fireless temperature [B] ignition temperature [C] static temper [D] optimum temperature

10) Haber Process is used to produce which among the following? [A] Potash [B] Ammonia [C] Urea [D] Nitrates

***ANSWERS*** 

1)C [  he first human-made plastic was made by Alexander Parkes in 1855, when he synthesized celluloid. The new discovery found its use in photographic films  but it could not be used for making containers or insulators for electric circuits.  The first true plastic was made in 1909 by Leo Baekeland, who synthesized Bakelite. The hard plastic could be used to make handles, auto parts, etc. The First World War witnessed improvements in the manufacture of polystyrene and polyvinyl chloride, which found use in plumbing equipment and electric wire insulation. Nylon was synthesized in the 1930s. By 1950, plastics became quite popular and as a result we can see them everywhere today]. 

2)B, 3)C, 
4)C.  [Pure diamond should transmit visible light and appear as a clear colorless crystal. Colors in diamond originate from lattice defects and impurities. The diamond crystal lattice is exceptionally strong and only atoms of nitrogen, boron and hydrogen can be introduced into diamond during the growth at  significant concentrations (up to atomic percents). Nitrogen gives yellowish color while the Boron gives bluish color. ] 

5)B. 6)A 7)A 8)A 9)B 10)B

No comments:

Post a Comment

General Science **VITAMINS**

Vitamins are necessary auxiliaries in metabolism. They combine with specific proteins, as parts of various oxidative enzyme systems which ...