1st sem chem.docx.about chemistry in engineering

**Chemistry: A Brief Description**

Chemistry is the branch of science that studies the composition, structure, properties, and changes of matter. It explores how substances interact with each other and with energy, helping us understand the building blocks of the universe at the atomic and molecular levels.

Often called the "central science," chemistry connects and overlaps with other scientific disciplines like biology, physics, environmental science, and medicine. It plays a vital role in everyday life—from the food we eat and the medicines we take, to the cleaning products we use and the materials in our clothing and technology.

Chemistry is divided into several branches, including organic chemistry (the study of carbon-containing compounds), inorganic chemistry, physical chemistry, analytical chemistry, and biochemistry. Each branch helps scientists solve real-world problems, develop new materials, and make discoveries that improve our quality of life.

Whether it's creating new drugs, developing sustainable fuels, or understanding environmental pollution, chemistry is essential to innovation and scientific progress.

1. **Write the Schrodinger wave equation and explain the terms involved in it. What is the
significance of Ψ
2
?
Q2.What do you mean by Eigen function and Eigenvalues?
An equation, where the operator, operating on a function, produces a constant times the function, is
called an eigenvalue equation.
The function is called an eigenfunction, and the resulting numerical value is called the eigenvalue.
Eigen here is the German word meaning self or own
Q3.The bond order of N
+
2 ion is less then then that of N2 whereas the bond the order of O
+
2 is
greater than that of O2. Explain with the help of molecular orbital theory.
The bond dissociation energy is related to the bond order of the molecule. When the
bond order is high, then high energy is required to break the bond so the bond
dissociation energy will be high.
According to molecular orbital theory, the number of electrons in an antibonding
molecular orbital of N2 is 10 and the number of electrons in bonding orbital is 4.
The bond order is calculated as shown below.
⇒B.O=(10−4)/2
⇒B.O=6/2
⇒B.O=3
In N2
+
number of electrons in antibonding molecular orbital is 9 and the number of
electrons in bonding orbital is 4.
The bond order is calculated as shown below.
⇒B.O=(9−4)/2⇒B.O=5/2⇒B.O=2.5
As, the bond order of N2 is more than N2+ therefore then bond dissociation energy
of N2 is more than N2+.
The number of electrons in the antibonding molecular orbital of O2is 10 and the
number of electrons in bonding orbital is 6.
The bond order is calculated as shown below.
⇒B.O=(10−6)/2⇒B.O=4/2⇒B.O=2
In O2+, the number of electrons in antibonding molecular orbital is 10 and the number
of electrons in bonding orbital is 5.
The bond order is calculated as shown below.
⇒B.O=(10−5)/2⇒B.O=5/2⇒B.O=2.5
As, the bond order of O2+ is more than O2therefore then bond dissociation energy
of O2+ is more than O2

2. Q4. Explain addition and condensation polymerisation with suitable examples
and state the differences between these polymerisation.
a) Addition polymers :Those polymers that are obtained by the addition of
monomeric units are called addition polymers. The molecular weight of such a
polymer is an exact multiple of the molecular weight ofof the monomer.
Molecular weight of polymer = n × molecular weight of monomer.
For example, polyethene, PVC, etc.
b) Condensation polymers:A polymer formed by the condensation of two or
more
than two monomers with the elimination of simple molecules like water,
ammonia and hydrochloric acid is termed as a condensation polymer. The
molecular weight of such a polymer is not an exact multiple of the molecular
weight of the monomer.
For example, Nylon 66 is obtained by the condensationof two monomers,
hexamethylenediamine and adipic acid with the loss of watermolecules.
Q5.What are nanomaterials? Write down the applications of nanomaterial
in the field of catalyst.
Nanomaterials are usually considered to be materials with at least one external dimension that
measures 100 nanometres or less or with internal structures measuring 100 nm or less. They may be
in the form of particles, tubes, rods or fibres.

3. Main applications of nanocatalysts in water purification; fuel cell; energy storage; in composite solid
rocket propellants; bio diesel production; in medicine; in dye; application of carbon nano tubes and
several other point of application are discussed here in detail.
Q6. What are the different types of carbon Nanotubes CNTs ? Write down two
important characteristics and applications of CNT.

4. Q7. What is corrosion ? Explain rusting of iron with the help of electrochemical
theory.
Definition: It’s defined as a process of gradual deterioration/degradation of metal
from its metal surface (except gold & platinum) due to unwanted chemical or
electrochemical reaction of metal with its environment. Examples: rusting of iron,
formation of green layer of basic.
Q8. Discuss two factors affecting the rate of corrosion?
Factors affecting the rate of corrosion:
1. Reactive metals:
In highly reactive metals, the rate of corrosion is very higher.
2. Temperature:
Due to the increase in temperature, the rate of corrosion also increases.
3. Presence of impurities:
The rate of corrosion increases when a metal is exposed to water especially saltwater.
Q9. What is Lambert Beer Law? Derive mathematical expression for lambert beer law.

5. Beer–Lambert law: It is the combined form of Beer’s law and Lambert’s law. According
to this law when a beam of monochromatic light is passed through asolution, the
decrease in intensity of radiation with thickness of the absorbing materialis directly
proportional to the intensity of incident radiation as well as to theconcentration of the
solution.

6. Q10.What are galvanic and pitting corrosion?Explain galvanic corrossion with one
example.
(a) Pitting corrosion : It is also an example of differential aeration corrosion. It is
alocalised type of corrosion and occurs in areas of pits, cavities and pinholes that
penetratedeeply within the metals. The pit is oxygen deficient and acts as anode,
whereas the planesurface is oxygen-rich and acts as cathode. As the area of anode is
small the rate ofcorrosion will be high. Anodic metal dissolves and the pit gradually
deepens resulting inthe weakening of the metal in these areas. If the pits are small they
may be covered bycorrosion products. Therefore, it is difficult to detect pitting
corrosion till sudden failureof the metal occurs. Pitting of metal generally occurs
because of breakdown or cracking in the protective filmon the metal surface at specific
points. It may be due to scratches, surface roughness, chemical attack, stresses and
strains, etc. Pitting is common in aluminium alloys, copperalloys, stainless steels and
some nickel alloys.
(b) Galvanic corrosion :It is also called bimetallic corrosion or differential
metalliccorrosion. It occurs when two dissimilar metals (for example, Zn and Cu) are

7. electricallyconnected and exposed to an electrolyte and then the metal higher in the
electrochemicalseries undergoes corrosion.
For example, if Zn and Cu are connected, Zn acts as anode and undergoes corrosion,
whereas Cu acts as cathode
Mechanism: In a Zn – Cu couple
At anode Zn -----------Zn
2+
+ 2e
-
– The reaction at the cathode depends upon the environment
Acidic environment 2H
+
+ 2e
-
------------- H2 (evolution of hydrogen)
Alkaline or neutral environment 1/2O2 + H2O + 2e
--------------------->
2OH
–
(absorption of oxygen)
Zn
2+
and 2OH
–
ions interact to form Zn(OH)2. Hence, Zn dissolves and Cu is protected.
Q11. Give the average chemical composition of Portland cement. Explain briefly
the chemistry of setting and hardening of cement.

8. Setting and Hardening of Cement
When water is mixed with cement paste to form a fluid paste, hydration of cement takes
place. The mixture eventually becomes stiff and then hard. This process is known as
setting. After hydration, anhydrated compounds becomehydrated which have less
solubility. Hence they are precipitated as insoluble gels or crystals. These have the
ability to surround sand, crushed stones (in mortars on concretes) on other inert
materials and bind them very strongly.
The physical changes occurring in the setting and hardening of cement maybe
summarized diagrammatically as follows:
uv
Q12. What are lubricants and lubrications? Write theimportant functions of a lubricant.
Lubrication

9. Lubrication can be defined as the application of some materials between two objects moving relative
to each other to allow smooth operation as much as necessary. Either oil or grease is used for rolling
bearings to prevent noise, wear and tear, and heat from being generated from their rolling and
sliding movements, and in some special cases, solid lubricants are occasionally used.
Lubricant
A lubricant (sometimes shortened to lube) is a substance that helps to reduce friction between
surfaces in mutual contact, which ultimately reduces the heat generated when the surfaces
move.Lubricants can be largely divided into two groups, namely mineral oil base lubricants and
synthetic lubricants.
Function of Lubricants:
(1) It reduces wear and tear of the surfaces by avoiding direct metal to metal contact between the
rubbing surfaces, i.e. by introducing lubricants between the two surfaces
(2) It reduces expansion of metal due to frictional heat and destruction of material
(3) It acts as coolant of metal due to heat transfer media
(4) It avoids unsmooth relative motion
(5) It reduces maintenance cost
(6) It also reduces power loss in internal combustion engines.
Q13. What is the significance of ψ and ψ
2
?
ψ is a wave function and refers to the amplitude of electron wave i.e. probability amplitude. It has got
no physical significance. The wave function ψ may be positive, negative or imaginary.
[ψ]
2
 is known as probability density and determines the probability of finding an electron at a point
within the atom. This means that if:
(i) is zero, the probability of finding an electron at that point is negligible.
(ii) [ψ]
2
 is high, the probability of finding an electron is high i.e. electron is present at that place for a
long time.
(iii) [ψ]
2
 is low. The probability of finding an electron is low i.e. electron is present at that place for a
shorter time.
Q14.Give two examples of commercially prepared conducting polymer.How conductivity of a
polymer can be increased by doping method?
Examples: polyacetylene (PA), polyaniline (PANI), polypyrrole (Ppy)
 The conductivity of a conductive polymer is due to the charge formed by the dopant, as the
doping level increases, more charges are formed in the polymer and, thus, results in a greater
conductivity. The conductivity of a conductive polymer is also temperature dependent, because
as the temperature increases the molecules becomes farther from each other. Thus, the doping
effect is more effective and, consequently, the amount of charges, which is the doping level of
the polymer is greater, increasing the conductivity.

10. Q15. Note on :
Infrared spectroscopy : Infrared (IR) spectroscopy is an absorption method widely used
in both qualitative and quantitative analyses. The infrared region of the spectrum includes
electromagnetic radiation that can alter the vibrational and rotational states of covalent bonds in
organic molecules.
Applications:
1.Identification of functional group and structure elucidation
2. Identification of substances
3.Studying the progress of the reaction
4.Detection of impurities
5.Quantitative analysis
NMR Spectroscopy:Nuclear magnetic resonance (NMR) spectroscopy is the study of
molecules by recording the interaction of radiofrequency (Rf) electromagnetic radiations with
the nuclei of molecules placed in a strong magnetic field.
Applications:
To determine structure of proteins, aminoacid profile, carotenoids, organic acids, lipid fractions, the mobility
of the water in foods.
NMR spectroscopy is also used to identify and quantify the metabolites in foods.
Q16.What is Galvenic series? How does it differ fromelectrochemical series.
Galvanic series It is a list of metal and alloys based on their relative potentials in a specified
environment. The environment generally used is seawater. Galvanic couple A pair of dissimilar
metals in contact with an electrolyte.
Galvanic series and electrochemical series differ in that galvanic series depicts the order of nobility of metals
and semimetals, whereas electrochemical series depicts the order of standard electrode potentials of chemical
elements.
Q17. What is green synthesis? Give one example of a green synthetic reaction explaining the reason why it is
green
Q18.Explain top down and bottom up approaches for synthesis of nanomaterials.

11. The top-down approach means reduce the size of the structure toward the nanoscale. While the
bottom-up approach is the formation of large nanostructure from smaller atoms and molecule
Q 19. What are the refractories? Give two essential properties of a good refractory material.
Or
What are refactories ? How are they classified ? Give one example of each class of refractories.

12. Example: Carbon graphite(most inert), Chromite refractories & alumina refractories.
Q20. Explain the principle of UV visible spectroscopy.
Q21. What is cathodic protection?
The principle involved is that the metal to be protected is made to behave like a cathode.
Alloys/metals like steel, brass, copper and lead can be protected in all types of soils and almost all
sorts of aqueous media by cathodic protection method. This technique is also employed to prevent
pitting corrosion in stainless steel or aluminium and can also be used to prevent stress corrosion
cracking in brass, mild steel, stainless steel, magnesium and aluminium. This can be done in two
ways
(i) Sacrificial Anode Cathodic Protection Method (SACP) In this method, the metal structure to be
protected is connected to a more reactive metal. For example, if an iron structure is to be protected
it is connected to a more reactive metal like Zn or Mg. The more reactive metal behaves as an anode

13. and the iron structure becomes cathodic. Thus, the iron structure is protected and the anode
undergoes corrosion. After sometime, the anode is corroded completely and is replaced with a fresh
anode. This anode (Zn or Mg), which is sacrificed to protect the base metal is called the sacrificial
anode and the method is called sacrificial anode cathodic protection method. This type of protection
method is used in industry to protect buried pipelines, underground cables, ship hulls and even in
railway tracks.