class iv jkssb paper held on 28 Feb 2021

JKSSB Science MCQ (TOPIC 1 ) FAA

4G services in JK

 4G services restored in JK after 500 plus days. 

People from all spheres of life suffer a lot. 

Only a few with access to Wi-Fi  enjoy the lockdown  and the crucial year of pandemic.  

JKSSB CLASS IV 27 FEB PAPER 2021

Damodar Veer Savarkar died on 26th Feb. 1966 was one of the great revolutionary who changed the demography of India  🇮🇳 

JKPSC CSE 2021 Notification (Final)

Date of online Form submission (Start) 11March 2021 

Last Date of Submission of Application forms :- 12 April 2021 

Date of PT:- 11 July 2021 

Date of Mains :- 04 OCT.  2021 

Age :- General =37 , Reserved = 39 & PH =40 

Qualification:- Any Graduate 🎓 

Atmosphere

EARTH’S ATMOSPHERE

The atmosphere is a thick gaseous envelope that surrounds the earth and extends thousands of kilometers above the earth’s surface. Much of the life on the earth exists because of the atmosphere otherwise the earth would have been barren. In fact, the atmosphere directly or indirectly influences the vegetation pattern, soil type and topography of the earth.

Composition of the Atmosphere

The atmosphere is a mixture of several gases. It contains huge amount of solid and liquid particles collectively known as aerosols. Pure dry air consists mainly of Nitrogen, Oxygen, Argon, Carbon Dioxide, Hydrogen, Helium and Ozone. Besides, water vapour, dust particles, smoke, salts, etc. are also present in the air in varying quantities.

The chemical composition of atmosphere up to an altitude of about 90 km is uniform in terms of major gases-Nitrogen and Oxygen. This layer is called Homosphere. Above 90 km, the proportion of the gases changes with progressive increase in the proportion of lighter gases. This layer is known as Heterosphere. Nitrogen and Oxygen comprise 99% of the total volume of the atmosphere. But Nitrogen does not easily enter into chemical union with other substances.

It serves mainly as an agent of dilution and remains chemically inactive. Oxygen combines with all the elements easily and is most combustible. Carbon dioxide constitutes a small percentage of the atmosphere. It can cause the lower atmosphere to be warmed up by absorbing heat from the incoming short wave solar radiation from the sun and reflecting the long wave terrestrial radiation back to the earth’s surface.

Carbon dioxide is utilized by the green plants in the process of photosynthesis. Water vapour and dust particles are the important variables of weather and climate. They are the source of all forms of condensation and principal absorbers of heat received from the sun and radiated from the earth. Water vapour comprises 3-4% of the total volume of air.

However, the amount of water vapour present in the atmosphere decreases from the equator towards the poles. Nearly 90% of the total water vapour lies below 6 km of the atmosphere.

Structure of the Atmosphere

The atmosphere consists of almost concentric layers of air with varying density and temperature.

a) Troposphere:

• Lowest layer of the atmosphere
• The height of troposphere is 16 km thick over the equator and 10 km thick at the poles.
• All weather phenomena are confined to troposphere (e.g. fog, cloud, frost, rainfall, storms, etc.)
• Temperature decreases with height in this layer roughly at the rate of 6.5° per 1000 metres, which is called normal lapse rate.
• Upper limit of the troposphere is called tropopause which is about 1.5 km.

b) Stratosphere:

• The stratosphere is more or less devoid of major weather phenomenon but there is circulation of feeble winds and cirrus cloud in the lower stratosphere.
• Jet aircrafts fly through the lower stratosphere because it provides conducive flying conditions.
• Ozone layer lies within the stratosphere mostly at the altitude of 15 to 35 km above earth’s surface.
• Ozone layer acts as a protective cover as it absorbs ultra-voilet rays of solar radiation.
• Depletion of ozone may result in rise of temperature of ground surface and lower atmosphere.
• Temperature rises from -60°C at the base of the stratosphere to its upper boundary as it absorbs ultra-voilet rays.
• Upper limit of the Stratosphere is called stratopause.

c) Mesosphere

• Mesosphere extends to the height of 50- 90 km.
• Temperature decreases with height. It reaches a minimum of -80°C at an altitude of 80-90 km
• The upper limit is called mesopause.

d) Thermosphere

• It lies at 80 km to 640 km above the earth’s surface.
• It is also known as ionosphere.
• Temperature increases rapidly with increasing height.
• It is an electrically charged layer. This layer is produced due to interaction of solar radiation and the chemicals present, thus disappears with the sunset.
• There are a number of layers in thermosphere e.g. D-layer, E-layer, Flayer and G-layer.
• Radio waves transmitted from earth are reflected back to the earth by these layers.

e) Exosphere

• This is the uppermost layer of the atmosphere extending beyond the ionosphere.
• The density is very low and temperature becomes 5568°C.
• This layer merges with the outer space.

40 Oneliner general science + 20 MCQ's @General Science (Chemistry )

 Chemical properties of substances & their uses 

Q1. Salt that  is connected with Mahatama Gandhi Dandi March ?

Ans Common Salt ( NaCl)  or Rock Salt Or Sodium chloride 

Q2. Salts are formed by reaction of acid & base , the reaction is called :-

Ans Neutralisation reaction 

Q3. The pH of Salt of Strong Acid & Strong bas is 

Ans 7 ( Neutral) 

Q4. The pH of Salt of Strong Acid & Weak base is 

Ans Less than 7 ( Acidic salt) 

Q5. The pH of salt of strong base & weak acid is 

Ans Greater than 7 ( basic salt) 

Q6.  sodium hydroxide (NaOH) is also called as 

Ans Caustic Soda 

Q7. Aqueous solution of NaCl is called as 

Ans Brine 

Q8. Chlor-alkali process is used for preparation of 

Ans NaOH   ( along with side product chlorine & Hydrogen ) 

Q9 Chemical used for de-greasing metals , soaps & detergents , paper making , artificial fibres is 

Ans NaOH 

Q10. Chemical used in fuels, margarine, hydrogenation , ammonia formation is 

Ans Hydrogen 

Q11. Chemical substance used in water treatment, PVC, CFC's, pesticides , disinfectant , swimming pools is '

Ans Chlorine 

Q12. In chlor-alkali process Hydrogen is liberated at 

Ans cathode 

Q13. In Chlor -alkali process Chlorine is liberated at 

Ans Anode 

Q14. Bleaching powder ( calcium Oxychloride ) is chemically 

Ans CaOCl2 

Q15. slaked lime is 

Ans Calcium Hydroxide = Ca(OH)2

Q16. Baking soda or Sodium bicarbonate or sodium hydrogen carbonate is 

Ans NaHCO3 

Q17. .....is used in making crispy pakoras 

Ans baking soda 

Q18. .....reacts with acids to liberate CO2 & Causes bread or cake to rise making them puffy Or spongy & soft 

Ans baking Soda 

Q19. Antacids are 

Ans Mild or weak base that neutralise Gastric acid 

Q20. baking soda acts as 

Ans Antacid 

Q21. The number of molecules of  water of crystallisation in washing soda 

Ans 10      ( Na2Co3 . 10 H2O ) 

Q22. washing Soda is also called 

Ans :- sodium carbonate 

Q23. Washing soda is ----salt 

Ans Basic salt 

Q24........is used in removing permanent hardness of water, Cleansing agent , soap & paper industries, borax formation -

Ans :- Sodium carbonate 

Q25. What is P.O.P ;-

Ans Plaster of Paris 

Q26. what is chemical name of P.O.P 

Ans calcium sulphate hemi-hydrate ( CaSO24. 1/2 H2O ) 

Q27. What is chemical formula of Gypsum 

Ans CaSO4. 2H2O 

Q28. When Gypsum is heated at 400K , it form 

Ans CaSO4 ( dead burnt Plaster ) 

Q29 When gypsum is heated at 373K , it forms 

Ans P.O.P 

Q30. .....changes the chemical composition of substance 

Ans Chemical reaction or chemical change 

Q31. Souring of milk is 

Ans Chemical change 

Q32. Burning of wood is '

Ans Chemical change 

Q33. Stretching of springs is 

Ans Physical change 

Q34. melting of Wax is 

Ans Physical change 

Q35. melting of ice is '

Ans physical change 

Q36. A solution reacts with crushed egg-shells to give a gas that turns lime-water milky . The solution contains 

Ans HCl ( Hydrochloric acid ) 

37. A solution turns red litmus blue , its pH is likely to be 

Ans    > 7 ( basic ) 

Q38. Chemical or medicine used for treating indigestion 

Ans Antacid 

Q39. Ant sting & Nettle sting  consists of 

Ans Methanoic acid ( formic acid = HCOOH) 

Q40. Milk of Magnesia , acts as antacid is 

Ans Mg(OH)2 - Magnesium Hydroxide 

Chemistry in Everyday life 

1. The use of chemicals for the treatment of diseases is called

a) Chemotherapy                b) radiotherapy  

c) Physiotherapy                 d) Isothermtherapy

2. Aspirin is a/an

a) Antiseptic           b) Antipyretic

c) Analgesic            d) Both - b & c

3). 2-Acetoxybenzoic acid is called:-

a) Antiseptic   b) Aspirin   c) Antibiotic   d)None

4. Which of the following is used for inducing sleep?

a) Paracetamol           b) Bithional  

c) Chloroquine           d) Barbituric acid derivative

5. Which of the following is hypnotic ?

a) Acetaldehyde              b) Metaldehyde 

c) Paraldehyde                 d) NOTA

6. Arsenic drugs are mainly used in the treatment of

a) Jaundice   b) typhoid  c) Syphillis d) cholera

7. Amoxicillin is semi-synthetic modification of

a) penicillin                 b) streptomycin

 c) tetracycline           d)None

8. Commonly dettol is an antiseptic & is a mixture of

a) Cresol + Phenol   b) Chloroxylenol+terpeneol

c) phenol+terpeneol   d) NOTA

9. which of the following is employed as a tranquilizer?

a) naproxen          b) tetracycline  

c)Equanil              d) Mifepristone

10. Which of the following is not antihistamine

a) Benadryl  b) Avil  c) cetirizine   d) rantidine

11.A broad spectrum antibiotic

a)PCM                  b) penicillin

 c) Aspirin            d) chloramphenicol

12. Matched ( Already ) 

List 1	List 2
A. iodoform	I.Antiseptic
B. Iodex(methylsalicylate)	ii.  Pain balm
C. Diethyl ether	iii.Anesthetic
D. BHC	iv. Insecticide

 13. which of the following is bacteriostatic & broad spectrum antibiotic

a) Chloramphenicol        b) Penicillin

c) Ofloxacin                      d) aminoglycosides

14.  In India, penicillin is manufactured at Hindustan Antibiotics in---- & is private sector industry

a) Pimpri   b) Nashik  c) Solapur d) udgir

15. Paul Ehrlich (German bacteriologist) synthesized medicine-Arsphenamine(Salvarsan) is containing ‘As’ metal  used as

a) Antibiotic             b) Analgesic

 c) Antipyretic          d) None

16. Which of the following form the base of talcum powder?

a) Magnesium hydrosilicate     b) Zinc stearate

c) sodium aluminium silicate   d) chalk

17. The common vehicle used in perfumes is

a) EtOH-H₂O mixture      b) Phenol+H₂O mixture

c) Phenol-EtoH-H₂O mix.   d) Phenol+ H₂O mix.

18. Phenol is used as

A) Antiseptic    b) Disinfectant      c)     Both a&b     d) None

19. NAD’s include :-

a) Antimicrobials       b) tranquilizers

c) Analgesics             d) Both b & c. 

20 . Vitamin-E is chemically called 

A) Tocopherol     B) Retinol 

C) Riboflavin       D) Niacin 

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