Chemistry Questions for Railway & SSC CGL Exam 2018 : 23rd June

Dear Students,

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. The exam will be conducted in the months of May 2018. 

रेलवे बोर्ड अपने उम्मीदवारों के लिए भव्य और प्रतिष्ठित कार्य पदों की पेशकश करता है. और हर साल ऐसा नहीं होता है कि हमें रेलवे की ओर से अधिसूचना मिलती है. लेकिन वर्तमान वर्ष 2018 आपके लिए बहुत सुखद वर्ष है क्योंकि इसमें लगभग 90,000 सीटों को वैध उम्मीदवारों द्वारा भरा जाएगा. आपके पास बहुत अच्छा अवसर है और आपको इसे एक बेहतर रणनीति से प्राप्त करना होगा. परीक्षा मई 2018 के महीने में आयोजित की जायेगी.

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Q1. Which type of colloidal system is expressed in the fog: 
कोहरे में किस प्रकार की कोलाइडियल प्रणाली व्यक्त की जाती है:
(a) Liquid in a gas/ एक गैस में तरल
(b) Gas in a liquid / एक तरल में गैस
(c) Solid in a gas / एक गैस में ठोस
(d) Liquid in Liquid /तरल में तरल
Show Answer
Sol. When the water vapour in the air condensed to form small drops of water, the fog is formed. When the temperature of air during winter season reaches near to dew point, the water vapour gets condensed around small particles of dust and remains suspended in the air because of their low weight.

Q2. The technique of chromatography is used to- 
क्रोमैटोग्राफी की तकनीक किसके लिए उपयोग की जाती है-
(a) Identify colour substances / रंग पदार्थों की पहचान करें
(b) Determine the structure of substances / पदार्थों की संरचना का निर्धारण करें
(c) Dry distillation of colouring substances / रंगीन पदार्थों का सूखा आसवन
(d) Separate the substances from a mixture / मिश्रण से पदार्थ अलग करना
Show Answer
Sol. Chromatography is a separation technique used to separate the different components in a liquid mixture. The separation is based on differential partitioning between the mobile and stationary phases. Chromatography may be preparative or analytical. The purpose of preparative chromatography is to separate the components of a mixture for more advanced use and thus a form of purification.

Q3. The element found maximum in the earth’s crust is- 
पृथ्वी की परत में अधिकतम कौन सा तत्व पाया जाता है
(a) Oxygen / ऑक्सीजन
(b) Nitrogen / नाइट्रोजन
(c) Manganese / मैंगनीज
(d) Silicon / सिलिकॉन
Show Answer
Sol. The element found the maximum in the soil layer is Oxygen 46.8% followed by Silicon 27.72%, Calcium 3.65% and Carbon 0.6%.

Q4. Which is the most abundant element after Oxygen on earth’s surface? 
पृथ्वी की सतह पर ऑक्सीजन के बाद सबसे प्रचुर मात्रा में तत्व कौन सा है?
(a) Silicon / सिलिकॉन
(b) Carbon / कार्बन
(c) Sodium / सोडियम
(d) Chlorine /क्लोरीन
Show Answer
Sol. The most abundant element on earth’s surface after Oxygen is Silicon. It was discovered by J.J Berzelius in 1824. The word ‘Silicon’ was taken from the Latin word silex. Silicon chips are used as a semiconductor in computers.

Q5. Which of the following is the most abundant element in the Universe?
में निम्नलिखित में से कौन सा तत्व ब्रह्मांड में प्रचुर मात्रा में है 
(a) Hydrogen / हाइड्रोजन
(b) Oxygen / ऑक्सीजन
(c) Nitrogen / नाइट्रोजन
(d) Carbon / कार्बन
Show Answer
Sol. The most abundant element in the Universe is Hydrogen, which makes up about ¾ of all matter. Helium makes up most of the remaining 1/4(25%). Thus, it is clear that hydrogen is the most common and abundant element in the Universe. While the most abundant element in the earth’s crust is Oxygen making up 46.6% of earth mass.

Q6. The chemical composition of diamond is? 
हीरे की रासायनिक संरचना है?
(a) Carbon/ कार्बन
(b) Nitrogen/ नाइट्रोजन 
(c) Nickel / निकेल
(d) Zinc /जिंक
Show Answer
Sol. Chemically diamond is the purest form of carbon (crystal structure). Hence, it is a fundamental element. Sand is basically made up of Silicon and Oxygen, Marble is made up of Calcium, Carbon and Oxygen while sugar is mainly the mixture of Carbon, Hydrogen and Oxygen.

Q7. Which is the most reactive metal in the following ? 
निम्नलिखित में सबसे प्रतिक्रियाशील धातु कौन सी है?
(a) Sodium / सोडियम
(b) Calcium / कैल्शियम
(c) Iron/आयरन
(d) Potassium/ पोटैशियम
Show Answer
Sol. Potassium is the most reactive metal.
Reactivity series (or Electrochemical Series) of metals –
Potassium K Most reactive
Sodium Na
Barium Ba
Calcium Ca
Magnesium Mg
Aluminium Al
       From the above reactive series, we can see that Potassium is the most reactive metal.

Q8. Which is the hardest in the following? 
निम्नलिखित में सबसे ठोस कौन सा है?
(a) Diamond/ हीरा
(b) Glass / कांच
(c) Quartz / क्वार्ट्ज
(d) Platinum/ प्लैटिनम
Show Answer
Sol. Diamond is the hardest, least compressible and best thermal conductor among all natural materials.

Q9. The chemical structure of the pearl is- 
मोती की रासायनिक संरचना है-
(a) Calcium Carbonate / कैल्शियम कार्बोनेट
(b) Calcium Carbonate & Magnesium Carbonate / कैल्शियम कार्बोनेट और मैग्नीशियम कार्बोनेट
(c) Calcium Chloride / कैल्शियम क्लोराइड
(d) Calcium Sulphate /कैल्शियम सल्फेट
Show Answer
Sol. The chemical composition of pearl is 85% Calcium Carbonate, 10-14% Conchiolin and 2-4% of water (CaCO₃ and H₂O). Conchiolin is protein.

Q10. Monazite is an ore of-
मोनाज़िट किसका एक अयस्क है
(a) Zirconiun/ ज़र्कोनियम
(b) Thorium/ थोरियम
(c) Titanium/ टाइटेनियम
(d) Iron/आयरन
Show Answer
Sol. Monazite is an important ore for Thorium, Lanthanum and Cerium.The deposits in India are particularly rich in Monazite.Its extensive deposits are found in Southern India.

Q11. These days yellow lamps are frequently used as street light. Which one of the following is used in these lamps: 
इन दिनों पीले लैंप अक्सर सड़क की रोशनी के रूप में उपयोग किया जाता है. इन लैंप में निम्नलिखित में से क्या उपयोग किया जाता है:
(a) Sodium / सोडियम
(b) Neon / नियोन
(c) Hydrogen / हाइड्रोजन
(d) Nitrogen / नाइट्रोजन
Show Answer
Sol. There are 2 types of street light bulbs are used by municipalities. They are sodium vapor and mercury vapor bulbs. The mercury vapor bulbs are usually a white ambient light and sodium an orange/yellow light. Compared to LPS (Low-pressure sodium) lamps, high-pressure sodium lamps tend to have a longer life, less lumen per watt efficiency and most importantly a higher colour rendering index. 

Q12. 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
Show Answer
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.

Q13. Of how many carats is the pure gold? 
शुद्ध सोना कितना कैरेट होता है
(a) 22
(b) 24
(c) 28
(d) 20
Show Answer
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 by mass. Because of the softness of pure (24 carat 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.

Q14. The chemical name of limestone is? 
चूना पत्थर का रासायनिक नाम है?
(a) Calcium Carbonate / कैल्शियम कार्बोनेट
(b) Magnesium Chloride / मैग्नीशियम क्लोराइड
(c) Sodium Chloride / सोडियम क्लोराइड
(d) Sodium Sulphide / सोडियम सल्फाइड
Show Answer
Sol. Limestone is a sedimentary rock composed largely of the minerals Calcite and Aragonite which are different crystals form of Calcium Carbonate (CaCO3). Limestone binds with silica and other impurities to remove them from the iron.

Q15. The chemical formula of the plaster of Pars is- 
प्लास्टर ऑफ़ पेरिसके का रासायनिक सूत्र क्या है-
(a) CaSO₄
(b) CaSO₄½H₂O
(c) CaSO₄.H₂O
(d) CaSO₄.2H₂O
Show Answer
Sol. A group of gypsum cement, essentially hemihydrated Calcium Sulphate (CaSO4. 1/2H2O), a white powder that forms a paste when it is mixed with water and then hardens into a solid used in making a cast, mould and sculpture.

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