Chemistry Questions for Railway & SSC CGL Exam 2018: 14th july (With Video Solution)

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 month 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.

Q1. When did the Bhopal Gas tragedy happen? 
भोपाल गैस त्रासदी कब हुई थी? 
(a) 2-3 Dec. 1984 /2-3 दिसम्बर 1984
(b) 2-3 Nov. 1984 /2-3 नवंबर 1984
(c) 2-3 Dec. 1985 / 2-3 दिसम्बर 1985
(d) 2-3 Nov. 1985 /2-3 नवंबर 1985

Show Answer
Sol. The Bhopal Gas tragedy happened on 2-3 December 1984 at night.

Q2. According to weight, the percentage of Hydrogen in water (H_2 O), is-
वजन के अनुसार, पानी में हाइड्रोजन का प्रतिशत (H2O), है?
(a) 44.45%
(b) 5.55%
(c) 88.89%
(d) 11.11%

Show Answer
Sol. Percentage of composition is the percent by mass of each element present in a compound.
        In water H2O=2=16=18g/mol
        Molecular weight of water 18.015grams.
         No. of Hydrogen atoms present in water=2
         Percentage of Hydrogen in water=11.11%

Q3. Which one of the following fuels cause minimum air pollution? 
निम्नलिखित से कौन सा ईंधन न्यूनतम वायु प्रदूषण का कारण बनता है?
(a) Kerosene oil  /किरोसीन तेल
(b) Hydrogen /हाइड्रोजन
(c) Coal /  कोयला
(d) Diesel  / डीज़ल

Show Answer
Sol. Hydrogen is the purest combustion fuel. Water is generated from burning of Hydrogen. While coal, kerosene oil and diesel are known as fossil fuel or carbonic fuel which generates Carbon dioxide and many other harmful gases when it burns.

Q4. Heavy water is a type of-  
भारी जल ________ का एक प्रकार है.
(a) Metal/ धातु
(b) Moderator / मॉडरेटर
(c) Ore/ अयस्क
(d) Fuel/ ईंधन

Show Answer
Sol. Heavy water (D2O) Deuterium Oxide is used as a moderator and coolant in nuclear reactors because it slows down neutrons effectively and also has a low probability of absorption of neutrons. Deuterium is an isotope of Hydrogen which comprises both a neutron and a proton D2O is a form of water which reacts with Oxygen to form Deuterium Oxide (D2O), also known as heavy water.

Q5. The chemical formula of Heavy Water is? 
भारी जल का रासायनिक सूत्र क्या है ?
(a) H2O
(b) D2O
(c) H2CO3
(d) H2S

Show Answer
Sol. Heavy water (D2O) Deuterium Oxide is used as a moderator and coolant in nuclear reactors because it slows down neutrons effectively and also has a low probability of absorption of neutrons. Deuterium is an isotope of Hydrogen which comprises both a neutron and a proton D2O is a form of water which reacts with Oxygen to form Deuterium Oxide (D2O), also known as heavy water.

Q6. Heavy water has molecular weight: 
भारी जल का आणविक भार है-
(a) 18
(b) 20
(c) 36
(d) 54

Show Answer
Sol. Heavy water (D2O), also called deuterium oxide, water composed of deuterium, a hydrogen isotope with mass double that of ordinary hydrogen and oxygen. Thus, heavy water has a molecular weight of about 20, whereas the ordinary water has a molecular weight of about 18.

Q7. Permanent hardness of water is due to-
पानी की स्थायी कठोरता की वजह है:
(a) Chlorides and sulphates of Calcium and Magnesium / कैल्शियम और मैग्नेशियम के क्लोराइड और सल्फ़ेट्स
(b) Calcium bicarbonate sulphates / कैल्शियम बिकारबोनेट सल्फ़ेट्स
(c) Magnesium bicarbonate  / मैग्नेशियम बाइकार्बोनेट
(d) Clorides of Silver and Potassium  / सिल्वर और पोटेशियम के क्लोराइड्स

Show Answer
Sol. Drinking water is described as “hard” due to the presence of highly dissolved minerals specifically sulphates of Calcium and Magnesium Chloride. It is very difficult to wash clothes with hard water as it requires more soap and leaves a messy scum that cannot be washed out easily. When hard water is boiled at home or in industries, it leaves deposits of Calcium and Magnesium salts. These deposits reduce the efficiency of boilers, kettles and pipes and can cause blockages and even burst of the boilers. If salt level increases in irrigation water, it becomes harder for lawns and landscape plant to take up water even though the soil is moist. Consequently, more salty water requires extra effort to irrigate.

Q8. Which gas is used in the purification of drinking water? 
पीने के पानी के शुद्धिकरण में किस गैस का उपयोग किया जाता है?
(a) Helium / हीलियम
(b) Chlorine /क्लोरीन
(c) Fluorine / फ्लोरिन
(d) Carbon Dioxide / कार्बन डाइऑक्साइड

Show Answer
Sol. Chlorine is presently an important chemical for water purification (such as in water treatment plants), disinfectants and in bleach. Chlorine is usually used (in the form of hypochlorous acid) to kill bacteria and other microbes in drinking water supplies and public swimming pools.

Q9. By which process the sea water can be converted into pure water? 
किस प्रक्रिया से समुद्र के पानी को शुद्ध पानी में परिवर्तित किया जा सकता है? 
(a) Deliquescence /प्रस्वेद्य
(b) Efflorescence /प्रस्फुटन
(c) Electric separation /विद्युत् पृथक्करण
(d) Reverse osmosis  /विपरीत परासरण

Show Answer
Sol. Reverse osmosis (RO) is a water purification technology that uses a semipermeable membrane to remove larger particles from drinking water. 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.

Q10. The gas used in the manufacture of Vanaspati Ghee from Vanaspati Oil is- 
वनस्पति तेल से वनस्पति घी के निर्माण में इस्तेमाल गैस है- 
(a) Hydrogen /हाइड्रोजन
(b) Oxygen /ऑक्सीजन
(c) Nitrogen / नाइट्रोजन
(d) Carbon dioxide/ कार्बन डाइआक्साइड

Show Answer
Sol. Hydrogen gas is used in the manufacturing of Vanaspati ghee. To prepare the Vanaspati ghee, hydrogen gas is passed through vegetable oils under 8-10 atmospheric pressure in the presence of nickel powder at a temperature of 200°C, 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 and in other suitable conditions and are converted into saturated compounds. Vegetable oil + H_2  (200° C,Ni)/(8-10 atm)⇒ solid fat Vanaspati ghee (Saturated).

Q11. Which one of the following catalysts is used in hydrogenation of vegetable oils? 
वनस्पति तेलों के हाइड्रोजनीकरण के लिए निम्न में से कौन सा उत्प्रेरक उपयोग किया जाता है?
(a) Zinc / जस्ता
(b) Platinum / प्लेटिनम
(c) Nickel / निकेल
(d) Iron / लोहा

Show Answer
Sol. During hydrogenation, the vegetable oils are reacted with hydrogen gas at about 150° C. A nickel catalyst is used to speed up the reaction. The double bond is converted to single bond in the reaction. In this way, the unsaturated fats can be made into saturated fats.

Q12. Baking soda is- 
बेकिंग सोडा है-
(a) Sodium Chloride /सोडियम क्लोराइड
(b) Sodium Bicarbonate / सोडियम बाइकार्बोनेट
(c) Baking Soda /बेकिंग सोडा
(d) Sodium Hydroxide /सोडियम हाइड्रॉक्साइड

Show Answer
Sol. Sodium bicarbonate is also known as Baking Soda. The chemical formula of Sodium Bicarbonate is NaHCO3.

Q13. The chemical formula of washing soda is 
वॉशिंग सोडा का रासायनिक सूत्र है-
(a) NaOH
(b) Na2CO3
(c) NaHCO3
(d) Ca(OH)2 
Show Answer
Sol. Sodium Carbonate is known as washing soda. It is used as detergent. Its formula is Na_2 CO_3.

Q14. Which one of the following is coated on the photographic plate? 
निम्नलिखित में से किसे फोटो की प्लेट पर लेपित किया जाता है?
(a) Silver oxide / सिल्वर ऑक्साइड
(b) Silver bromide /सिल्वर ब्रोमाइड
(c) Silver chloride /सिल्वर क्लोराइड
(d) Silver iodide / सिल्वर आयोडाइड

Show Answer
Sol. High resolution photographic plates having a coating of exceedingly fine-grained photosensitive emulsions with sub microscopic crystals of silver bromide in gelatin

Q15. Fermentation of sugar leads to- 
चीनी के किण्वन से क्या प्राप्त होता है?
(a) Ethyl alcohol /एथिल अल्कोहल
(b)Methyl alcohol / मिथाइल अल्कोहल
(c) Acetic acid / सिरका अम्ल
(d) Chlorophyll / क्लोरोफिल

Show Answer
Sol. Ethyl alcohol is formed by the fermentation of sugar, which is made of glucose and fructose.