CENTRAL INSTITUTE OF PLASTICS ENGINEERING & TECHNOLOGY
Question Bank
COURSE : DPT
SEMESTER : I
SUBJECT : Engineering Chemistry
1. Explain the fundamental particles of atoms?
Ans. An atom consists of three fundamental particles. They are protons, neutrons and electrons. Protons and neutrons are present in the nucleus at the center of the atom called nucleons. Electrons revolve around the nuleus in an orbit. Proton has positive charge, Electron has negative charge and neutron has no charge.
2. Draw an atomic model for Carbon(6C12) atom.
Ans.
3. Define Atomic mass.
Ans. An atomic mass is defined as “the sum of total number of protons(p) and total number of
neutrons(n) present in the nucleus. It is denoted by the symbol ‘A’.A = p + n
4. What is Atomic number.
Ans. An atomic number is the total number of protons or the total number of electrons present in an atom.It is denoted by the symbol ‘Z’.
5. For an atom, the mass number is 23 and the neutron number is 12. What is the element of that atom?
Ans. Atomic mass = Total no. of protons + Total no. of neutrons
23= p + 12
p = 23 - 12
p = 11
Therefore, atomic number is 11. So the given element is “Sodium(Na)”
6. Write an electronic configuration for the following atoms.
i) Hydrogen (1H1)
ii) Lithium (3Li6)
iii) Carbon (6C12)
iv) Oxygen (8O16)
Ans. i) Hydrogen (1H1) - 1s1
ii) Lithium (3Li6) - 1s2 2s1
iii) Carbon (6C12) - 1s2 2s2 2p2
iv) Oxygen (8O16) - 1s2,2s2,2p4
7. Which type of bond present in sodium chloride (NaCl) and give the reason.
Ans. Ionic bond. Because in sodium chloride, the bond is formed by an electrostatic attraction of
positively charged sodium atom(Na+) and negatively charged chlorine atom(Cl-).
8. Which type of bond present in Hydrogen molecule (H2) and give the reason.
Ans. Covalent bond. Because in hydrogen molecule, the bond is formed by mutual sharing of electrons between two hydrogen atoms.
9. What is the rule for an atom to become stable. Explain it.
Ans. Octet rule. According to this rule, the outermost shell of an atom should possess eight electrons.
10. Explain the following terms based on Arrhenius Concept
i) Acid ii) Base
Ans. i) According to Arrhenius concept, “An acid is a substance which releases hydrogen ions(H+) in solution”
ii) According to Arrhenius concept, “A base is a substance which releases hydroxyl ions(OH-) in solution”
11. 0.4 g of NaOH was dissolved in 250 ml distilled water. Find the Normality of the solution?
Ans. Normality = Weight x 1000/Eq.wt x Volume
Normality = 0.4 x 1000/40x250
Normality = 0.4 N
12. Define Molarity of a solution.
Ans. Molarity of a solution is defined as the number of moles of solute present per litre of the solution.
13. Define Normality of a solution.
Ans. Normality of a solution is defined as the number of equivalent weights of solute present per litre of the solution.
14. What is Solution?
Ans. A homogeneous mixture of solute and solvent is called Solution.
15. Define pH of a solution.
Ans. pH of a solution is defined as the negative logarithm of hydrogen ion concentration.
pH = - log[H+]
16. Define pOH of a solution.
Ans. pOH of a solution is defined as the negative logarithm of hydroxyl ion concentration.pOH= -log[OH-]
17. What is the use of buffer solution?
Ans. Buffer solution is used to maintain the pH of a solution remains same. It plays a vital role in our body.
18. What is temporary hardness of water? Ans. Temporary hardness of water is caused by the presence of dissolved bicarbonates of calcium and magnesium. It is easily removed by boiling the water.
19. What is permanent hardness of water?
Ans. Permanent hardness of water is caused by the presence of chlorides and sulphates of calcium,magnesium, iron and other heavy metals. It cannot be easily removed by boiling the water.
20. What is soft water?
Ans. water is called soft water, if calcium and magnesium salts are absent in it.
21. What is alkane. Give two examples
Ans. Alkane is a saturated organic compound which has the molecular formula CnH2n+2. Examples are methane, ethane etc.,
22. What is alkene. Give two examples
Ans. Alkene is a unsaturated organic compound contains double bond. It has the molecular formula CnH2n. Examples are ethylene, propylene etc.,
23. What is alkyne. Give two examples
Ans. Alkyne is a unsaturated organic compound contains triple bond. It has the molecular formula CnH2n-2. Examples are ethyne, propyne etc.,
24. Classify the following compound based on functional group.
i) CH3-O-CH3 ii) CH3-OH iii) CH3COCH3 iv) CH3CHO
Ans. i) CH3-O-CH3 – Ether
ii) CH3-OH - Alchol
iii) CH3COCH3 - Ketone
iv) CH3CHO - Aldehyde
25. Write the name of the following compounds
i) CH3CH2CH2CH2CH3 ii) CH3CH3 iii) CH3CHO iv) CH3COCH3
Ans. i) CH3CH3 - Ethane
ii) C2H4 - Ethylene
iii) CH3CHO - Acetaldehyde
iv) CH3COCH3 - Acetone
26. Define the term fuels.
Ans. Fuel is a combustible substance, containing carbon as main constituent, which on proper burning gives large amount of heat. Eg., Wood, coal, petrol, dieses etc.,
27. What are fossil fuels?
Ans. The primary source of fuels are coals and petroleum oils. These are stored fuels available in earth’scrust and are generally called as fossil fuel.
28. Define Primary Fuels. Give examples.
Ans. The fuels which are found in nature is called natural fuels or primary fuels. Eg., Wood, dung, coal,crude oil etc.
29. What are secondary fuels? Give examples.
Ans. The fuels which are prepared from primary fuel is called artificial fuels or secondary fuels. Eg., Coke,petrol, tar, diesel etc.,
30. What are the types of fuels?
Ans. There are two types of fuels. They are natural or primary fuels and artificial or secondary fuels.Then, they are broadly classified into solid fuels, liquid fuels and gaseous fuels.
31. Define calorific value.
Ans. Calorific value is defined as “the total quantity of heat liberated, when a unit mass of the fuel is burnt completely”
32. What is cracking process?
Ans. Cracking is one of the most important processes in oil refining. It is the breaking of long chain hydrocarbons (Heavy Hydrocarbons) producing lighter products and gases.
33. Define fractional distillation.
Ans. Fractional distillation is a process by which components in a chemical mixture are separated into different parts (called fractions) according to their different boiling points. Fractional distillation is used to purify chemicals and also to separate mixtures to obtain their components.
34. Explain biogas production
Ans. Biogas is produced by the degradation of biological matter by the bacterial action in the absence of oxygen.
35. What is octane number?
Ans. Octane number is used to measure the antiknock properties of a liquid motor furl. Higher number indicating a smaller likelihood of knocking. It is also called a octane rating.
36. What is conductor?
Ans. Those substances which allow electric current to pass through them are known as conductors. Eg.,metals.
37. What is insulator?
Ans. Those substances which do not allow electric current to pass through them are known as nonconductors or insulators. Eg., glass, rubber.
38. What are the types of conductors?
Ans. There are four types of conductors. They are metallic conductors, electrolytic conductors, mixed conductors and semi conductors.
39. What is electrolytic conductors?
Ans. These are ionic compounds which conduct current either in solution or in fused state. They consist of charged particles called ions. These ions migrate in the presence of an applied electric field.
40. Explain Ohm’s law.
Ans. According to Ohm’s law, the strength of the current(I) flowing through a conductor is directly proportional to the potential difference(E) applied across the conductor and inversely proportional to the resistance of the conductor.I = E/R
41. What is an electrolytic cell?
Ans. A cell which consume electrical energy and a chemical change occurs is called an electrolytic cell.
42. What are semiconductors?
Ans. These consist of covalent crystal which are poor conductor in pure state and at normal
temperatures, but they become good conductors either at high temperature or in presence of small impurities. Eg., Silicon, Germanium.
43. Define System.
Ans. Thermodynamically a system is defined as any portion of matter under consideration which is separated from the rest of the universe by real or imaginary boundaries.
44. What is Surroundings?
Ans. Everything in the universe that is not the part of system and can interact with it is called as
surroundings.
45. What is Endothermic process?
Ans. A process when transformed from initial to final states by absorption of heat is called as an
endothermic process.
46. Explain first law of thermodynamics.
Ans. According to first law of thermodynamics, energy may be converted from one form to another form,but cannot be created or be destroyed.
47. What is extensive properties?
Ans. The properties that depend on the mass or size of the system are called as extensive properties.
Eg., Volume, mass, energy etc.,
48. What is intensive properties?
Ans. The properties that are independent of the mass or size of the system are known as intensive properties. Eg., refractive index, surface tension, density, boiling point etc.,
49. Define Adiabatic process.
Ans. Adiabatic process is defined as that one which does not exchange heat with its surroundings during the change from initial to final states of the system.
50. What is open system?
Ans. A system is said to be open if it can exchange both energy and matter with its surroundings. For eg., a open beaker containing an aqueous salt solution represents open system.
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