Previous Year Questions General Science for CDS & CAPF: 21st November



Previous year questions must be prepared when it comes to the preparation of CDS & CAPF examinations. Defenceadda is providing you with the previous year questions of General Science Section.

Q1. The polymeric fibre used as a substitute for wool in making synthetic blankets, sweaters, etc., is -
(a) Nylon 
(b) Teflon 
(c) Orlon 
(d) Bakelite

Q2. The cleaning of dirty clothes by soaps and detergents is due to a type of molecules called surfactants, which are present in soaps and detergents. The surfactant molecules remove the dirt by -
(a) Making the cloth slippery 
(b) Producing some gases between the dirt and the cloth 
(c) Dissolving the dirt 
(d) Forming some aggregates of themselves and take away the dirt in the core of the aggregates 

Q3. Which one of the following is not a mixture?  
(a) Toothpaste 
(b) Toilet soap 
(c) Baking soda 
(d) Vinegar 

Q4. Which one of the following reducing agents can also act as an oxidizing agent?  
(a) H2
(b) H2S
(c) SO2
(d) HI 

Q5. Consider the following statements regarding the properties and uses of glass wool.  
I. Glass wool has tensile strength greater than steel. 
II. Glass wool is fire proof. 
III. Glass wool has high electrical conductivity and absorbs moisture. 
IV. Glass wool is used to prepare fibre glass. 
Which of the statements given above are correct? 
(a) I and II 
(b) I, II and IV 
(c) II and IV 
(d) I, III and IV 

Q6. Which one among the following has been producing / can produce light by a chemical change? 
(a) Sun 
(b) Moon 
(c) Electric bulb 
(d) Lightning and thunder 

Q7. A woman desire to clean the surface of her gold ornaments by a chemical approach. For this she requires to use  
(a) aqua-regia 
(b) Concentrated H2SO4
(c) Concentrated NaOH
(d) Sodium thiosulphate solution 

Direction (Qs. 8 to 9) : The following questions consist of two statements. Statement I and Statement II. You are to examine these two statements carefully and select the answers to these items using the codes given below. 

Q8. Statement I: During the setting of cement, the structure has to be cooled by spraying water. 
Statement II: The constituents of cement undergo hydration during setting of cement and it is an exothermic reaction.
(a) Both the statements are individually true and Statement II is the correct explanation of Statement I. 
(b) Both the statements are individually true but Statement II is not the correct explanation of Statement I.
(c) Statement I is true, but Statement II is false. 
(d) Statement I is false, but Statement II is true.

Q9. Statement I : Superphosphate of lime can be assimilated by plants. 
Statement II : Superphosphate of lime is soluble in water. 
(a) Both the statements are individually true and Statement II is the correct explanation of Statement I. 
(b) Both the statements are individually true but Statement II is not the correct explanation of Statement I.
(c) Statement I is true, but Statement II is false. 
(d) Statement I is false, but Statement II is true.

Q10. Which one of the following is not a periodic property i.e., does not show any  trend on moving from one side to the other in the periodic table?  
(a) Atomic size 
(b) Valency 
(c) Radioactivity 
(d) Electronegativity 


SOLUTIONS
S1. Ans.(c)
Sol. Polyacrylonitrile or orlon is used as a substitute for wool in making synthetic blankets, sweaters etc. It is a polymer of acrylonitrile or vinyl cyanide. 

S2. Ans.(d)
Sol. The cleaning of dirty clothes by soaps and detergents is due to a type of molecules called surfactants. The surfactant molecules remove the dirt by forming some aggregates of themselves and take away the dirt in the core of aggregates. The spherical aggregate of surfactant molecules in water is called a micelle. 

S3. Ans.(c)
Sol. Sodium bicarbonate also known as baking soda, is the chemical compound with the formula NaHCO3.

S4. Ans.(c)

S5. Ans.(b)
Sol. Glass wool is an insulating material, obtained from fibre glass arranged into a texture similar to wool. 

S6. Ans.(a)
Sol. In a chemical change a new substance is formed. Sun has been producing light by nuclear fusion and it is a chemical change. 
S7. Ans.(a)
Sol. Aqua-regia is a mixture of concentrated nitric acid and concentrated hydrochloric acid in the ratio of 1 : 3. It is a very powerful oxidizing mixture and hence, used to clean the surface of gold ornaments. 

S8. Ans.(a)
Sol. During the setting of cement, the structure has to be cooled by spraying water because setting of cement is an exothermic process and involves hydration of calcium aluminates and calcium silicates. 

S9. Ans.(a)
Sol. Superphosphate of lime can be easily assimilated by plants because it is soluble in water. 

S10. Ans.(c)
Sol. Radioactivity is not a periodic property. It is a nuclear property. Atomic size, valency and electronegativity are periodic properties because they show a trend on moving from one side to the other in the periodic table. 


No comments