Railway Board offers opulent and revered job posts to its aspirants. And it is not every year that we get the notification from Railway offering a good number of vacant seats to the multitude aspirants. But the current year 2018 brought a pleasant surprise with almost 90,000 seats to be filled by the valid candidates. Opportunity is here but you have to welcome it with a provident strategy.
Q1. The most commonly used substance in fluorescent tubes are-
फ्लोरोसेंट ट्यूबों में सामान्यतः सबसे अधिक इस्तेमाल किया जाने वाला पदार्थ हैं-
(a) Sodium Oxide and Argon / सोडियम ऑक्साइड और आर्गन
(b) Sodium Vapour and Neon / सोडियम वाष्प और नियॉन
(c) Mercury Vapour and Argon / मरकरी वाष्प और आर्गन
(d) Mercuric Oxide and Neon / मेर्कुरिक ऑक्साइड और नियॉन
Sol. Fluorescent lamp tube is filled with a gas containing low pressure mercury vapour and Argon. Sometimes gases like Xenon, Neon or Krypton can also be used. The pressure inside the lamp is around 0.3% of atmospheric pressure.
Q2. Which one of the following metals is accessed in the native state?
निम्नलिखित में से कौन सी धातु का उपयोग मूल अवस्था में किया जाता है?
(a) Aluminium(अल्युमीनियम)
(b) Gold(सोना)
(c) Chromium(क्रोमियम)
(d) Zinc(जस्ता)
Sol. Among the metals, gold is the least reactive, so this was accessed the in the native (free) state. On the basis of reactivity, the decreasing order (From top to bottom) of metals is given below. Lithium (Li), Potassium (K), Barium (Ba), Strontium (Sr), Calcium (Ca), Sodium (Na), Magnesium (Mg), Aluminium (Al), Manganese (Mn), Zinc (Zn), Chromium (Cr), Iron (Fe), Cadmium (Cd), Cobalt (Co), Nickel (Ni), Tin (Sn), Lead (Pb), Copper (Cu), Mercury (Hg), Silver (Ag), Platinum (Pt), Gold (Au).
Q3. Which gas is not in the gaseous cycle?
गैसीय चक्र में कौन सी गैस नहीं है?
(a) N_2
(b) O_2
(c) Carbon / कार्बन
(d) H_2
Sol. Biogeochemical cycles can be classed as gaseous in which the reservoir is that air or the oceans (via evaporation) and sedimentary in which the reservoir is earth’s crust. Gaseous cycles include Nitrogen, Oxygen, Carbon and Water. Sedimentary cycles include Iron, Calcium, Phosphorus, Sulphur and other more earthbound elements.
Q4. Of how many carats is the pure gold?
शुद्ध सोना कितने कैरेट का होता है?
(a) 22
(b) 24
(c) 28
(d) 20
Sol. It is an extension of the older carat (Karat in North American spelling) system of denoting the purity of gold by fractions of 24, such as ’18 carat’ for an alloy with 75% (18 parts per 24) pure gold, it is usually alloyed with base metals for use in jewellery, altering its hardness and ductility, melting point, colour and other properties. Alloys with lower carat rating typically 22k, 18k, 14k or 10k contain higher percentages of copper or other base metals or silver or palladium in the alloy.
Q5. What is the shape of Sulphur hexafluoride molecule?
सल्फर हेक्साफ्लोराइड अणु का आकार क्या है?
(a) Trigonal pyramid / त्रिकोणीय पिरामिड
(b) Octahedral / अष्टभुजाकार
(c) Planar / प्लानर
(d) Tetrahedral / चतुष्फलकीय
Sol. Sulphur hexafluoride (SF_6) is an inorganic, colourless, odourless and non-flammable compound. SF_6 has an octahedral shape. It has 12 electrons around the central Sulphur atom. This means there are six electron pairs arranged in an octahedral shape.
Q6. Easily soluble in water-
पानी में आसानी से घुलनशील है-
(a) Carbon/कार्बन
(b) Nitrogen/नाइट्रोजन
(c) Ammonia/अमोनिया
(d) Iodine/आयोडीन
Sol. Ammonia being a polar molecule dissolves readily in water. This is due to the Hydrogen atoms of Ammonia which are bonded with a highly electronegative Nitrogen and the Hydrogen atoms of water molecules which are bonded with the highly electronegative Oxygen atom.
Q7. Which is used as Laughing gas is-
हास्य गैस (लाफिंग गैस) के रूप में उपयोग की जाने वाली गैस है-
(a) Nitrous Oxide / नाईट्रस ऑक्साइड
(b) Nitrogen dioxide / नाइट्रोजन डाइऑक्साइड
(c) Nitrogen Trioxide / नाइट्रोजन ट्रायऑक्साइड
(d) Nitrogen Tetra Oxide / नाइट्रोजन टेट्राऑक्साइड
Sol. Nitrous Oxide (N_2 O) is also known as laughing gas. It is a colourless gas with a sweet odour and taste. Inhalation leads to disorientation, euphoria, numbness, loss of coordination, dizziness and ultimately a loss of consciousness. It is also used as the anesthetic gas.
Q8. Which one of the following is also called Stranger Gas?
निम्नलिखित में से किसे अजनबी गैस भी कहा जाता है?
(a) Argon / आर्गन
(b) Neon / नीयन
(c) Xenon / क्सीनन
(d) Nitrous Oxide / नाइट्रस ऑक्साइड
Sol. Xenon is a chemical gas with symbol Xe and atomic number 54. It is a rare, odourless, colourless, tasteless, chemically unreactive gas. Xenon gas is also known as stranger gas as its volume is low in the atmosphere (0.08 parts per million of xenon). It was discovered in England by the Scottish chemist William Ramsay and British chemist Morris Travers in 1898.
Q9. The gas used to inflate the tyres of an aircraft is-
एक विमान के टायर में हवा भरने के लिए कौन सी गैस का प्रयोग किया जाता है?
(a) Hydrogen / हाइड्रोजन
(b) Nitrogen / नाइट्रोजन
(c) Helium /हीलियम
(d) Neon / नीयन
Sol. Nitrogen gas is used in the types of an aeroplane. This is because the nitrogen gas does not support combustion and can assist in preventing wheel fire when the aircraft lands (braking and high speed can produce dangerously high temperatures) unlike in oxygen. There are other benefits but effectively it is being the lowest cost gas that does not support combustion. It is preferred in comparison with the oxygen because nitrogen does not contain water. Thus, when the plane is at more height, gas in tyres does not get frozen.
Q10. Out of the following is not an alloy?
निम्नलिखित में से कौन सी एक मिश्र धातु नहीं है?
(a) Steel / स्टील
(b) Brass / पीतल
(c) Bronze / कांस्य
(d) Copper / कॉपर
Sol. Copper is a metal, however steel, brass and bronze are alloys.
Q11. Which among the following is white phosphorus?
निम्नलिखित में से कौन सा सफेद फास्फोरस है?
(a) P1
(b) P6
(c) P4
(d) P5
Sol. The most important form of elemental phosphorus from the perspective of applications and chemical literature is white phosphorus. It consists of tetrahedral P4molecules, in which each atom is bound to the other three atoms by a single bond.
हवाई जहाज और ट्रेन के डिब्बे के कुछ हिस्सों को बनाने के लिए किस मिश्र धातु का उपयोग किया जाता है?
(a) Copper / कॉपर
(b) Iron / आयरन
(c) Aluminium / एल्यूमिनियम
(d) None of these / इनमे से कोई नहीं
Sol. Low density and strength make Aluminium ideal for construction of aircraft, lightweight vehicles and ladders. An alloy of Aluminium called Duralumin is often used instead of pure Aluminium because of its improved properties. Easy shaping and corrosion resistance make Aluminium a good material for drinking cans and roofing materials.
पारा -धातु मिश्रण है-
(a) High colour alloy/ उच्च रंग मिश्र धातु
(b) Carbon mixed alloy/ कार्बन मिश्रित मिश्र धातु
(c) Mercury mixed alloy/ पारा मिश्रित मिश्र धातु
(d) Highly resisting alloy for malfriction/ अधिकतम घर्षण के लिए अत्यधिक प्रतिरोधी मिश्र धातु
Sol. An amalgam is a substance formed by the reaction of mercury with another metal. Almost all metals can form amalgams with Mercury, the notable exception being Iron.
Q14. Which one of the following alloys is called an amalgam?
निम्नलिखित में से किसकी मिश्र धातु को अमलगम कहा जाता है?
(a) Zinc / जिंक – Copper / कॉपर
(b) Copper / कॉपर – Tin / टिन
(c) Mercury/ पारा – zinc/ जिंक
(d) Lead / लेड – Zinc/ जिंक
Sol. An amalgam is a substance formed by the reaction of mercury with another metal.
Q15. Solder used in soldering metal pieces consists of any alloy of
सोल्डरिंग धातु के टुकड़ों में इस्तेमाल होने वाले सोल्डर किस मिश्र धातु के होते हैं?
(a) Tin and Zinc / टिन और जिंक
(b) Tin and Lead / टिन और लेड
(c) Tin, Zinc and Copper / टिन, जिंक और कॉपर
(d) Tin, Lead and Zinc / टिन, लेड और जिंक
Sol. The common composition of solder is 32% Tin, 68% Lead. This combination has a low melting point and is useful for soldering components that are sensitive to heat.
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