Chemistry Questions for NDA: 31st August

Dear Aspirants, Chemistry is an important subject in various exams like NDA, CDS, AFCAT, CAPF and other Police Exams. Here at Defence Adda we provide you with the quizzes based on the syllabus and pattern of these exams. The questions asked are of 10+2 level and preparing with a wide variety of questions will help you ace in these exams. Here is a quiz based on the latest syllabus of these exams based on topics like Metals, Non-metals, Oxidation and Reduction, Periodic Table etc to help you prepare with a wide variety of questions.

Q1. Which gas is known as ‘noble gas”? 
(a) Hydrogen 
(b) Oxygen 
(c) Helium  
(d) Carbon dioxide 

Q2. Which one of the following is coated on the photographic plate? 
(a) Silver oxide 
(b) Silver bromide 
(c) Silver chloride 
(d) Silver iodide 

Q3. Methane gas producing field is- 
(a) Wheatfield 
(b) Paddy field 
(c) Cotton field 
(d) Groundnut field 

Q4. A polymer used for making nonstick surface coating for utensils is- 
(a) Polyvinyl chloride
(b) Teflon 
(c) Polystyrene  
(d) Polypropylene

Q5. Which is used as laughing gas is- 
(a) Nitrous Oxide
(b) Nitrogen dioxide
(c) Nitrogen Trioxide
(d) Nitrogen Tetra Oxide

Q6. What is Nila thotha?
(a) Copper Sulphate
(b) Calcium Sulphate
(c) Iron Sulphate
(d) Sodium Sulphate

Q7.Which is the fundamental element of all organic compounds?
(a) Nitrogen
(b) Oxygen
(c) Carbon
(d) Silicon

Q8. The important metal used with iron to make it rust free- 
(a) Aluminium 
(b) Carbon 
(c) Chromium 
(d) Tin 

Q9. Which one of the following catalysts is used in hydrogenation of vegetable oils? 
(a) Zinc 
(b) Platinum 
(c) Nickel 
(d) Iron  

Q10. What is the shape of Sulphur hexafluoride molecule? 
(a) Trigonal pyramid 
(b) Octahedral 
(c) Planar 
(d) Tetrahedral  

S1. Ans.(c)
Sol. The noble gases make a group of chemical elements with similar properties under standard conditions, they are all odourless, colourless, monatomic gases with very low chemical reactivity. The six noble gases that occur naturally are Helium (He), Neon (Ne), Argon (Ar), Krypton (Kr), Xenon (Xe) and the radioactive Radon (Rn). 

S2. Ans.(b)
Sol. High resolution photographic plates having a coating of exceedingly fine-grained photosensitive emulsions with sub microscopic crystals of silver bromide in gelatin. 

S3. Ans.(b)
Sol. Paddy fields are a major source of atmospheric methane .

S4. Ans.(b)
Sol. Polytetrafluoroethylene (PTFE) is usually known as Teflon. This is especially used for making a non-stick surface coating for utensils.

S5. Ans. (a)
Sol. Nitrous Oxide (N2O) is also known as laughing gas. It is a colourless gas with a sweet odour and taste.  It is also used as the anesthetic gas. 

S6. Ans. (a)
Sol. Nila thotha is a compound of Copper and sulphate. Its chemical formula is CuSO4.5H2O.

S7. Ans. (c)
Sol. The organic compounds are a large class of chemical compounds in which one or more atoms of carbon are covalently linked atoms of other elements, most commonly Hydrogen, Oxygen or Nitrogen.

S8. Ans.(c)
Sol. Stainless steel alloy with a minimum of 10.5% Chromium content by mass. The presence of Chromium protects steel from corrosion, rust and make it high-temperature resistance. 

S9. Ans.(c)
Sol. During hydrogenation, the vegetable oils are reacted with hydrogen gas . 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. 

S10. Ans.(b)
Sol. Sulphur hexafluoride (SF6) is an inorganic, colourless, odourless and non-flammable compound. SF6 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. 

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