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Bio-Chemistry Interview Question and Answers
Give the example for electrophilic
substitution reaction.
The species, which accepts the electrons, are called Electrophilles (or)
Electrophilic reagents.
When the atom (or) group of atoms present in the organic compound is
replaced by another atom (or) group of atoms (electrophilic) is called
electrophilic substitution reaction.
What is addition
reaction?
When atoms (or) group of atoms are added, to form more saturated compound
it is called addition reaction.
How do you define free radical
addition reaction? Give an example.
When unsaturated compounds undergo addition reactions with free radicals,
it is called free radical addition reaction.
Ex; CH3-CH = CH2+HBr-----------> CH3-CH2-CH2Br
What is nucleophilic addition
reaction?
When the attacking species during the addition reaction is Nucleophilic,
it is nucleophilic addition reaction. Ex; Acetaldehyde cynohydrin
What is electrophilic addition
reaction?
When the attacking species during the addition reaction is Electrophile, it is called electrophilic addition reaction. Ex; (+) (-) (+) (-) (+) (-)
CH2Br-CH2BràH2C-CH2+BrBr-àH2C=CH2+Br2-
What are the favorable conditions
for formation of cat ions?
- Low Ionisational potential
- Lesser Charge
- More atomic size of atoms
forms cations easily
- Ions having Inert gases
configuration formed easily
What are the favorable conditions
for formation of Anions?
- High Electron affinity
- Small size
Less charge of an atoms form anion more easily
Define lattice
energy.
The energy released when one mole of ionic crystal is formed by the
combination of the corresponding gaseous (+ve) and (-ve) ions brought from
infinite distance is called lattice energy.
What happens if Lattice energy
increases?
- The Strength of ionic bond
- Stability of the Ionic
compound
- Ease of formation of the
Ionic bond Increases
What is Sublimation
energy?
The amount of energy required to convert one mole of solid substance to
vapor state is called Sublimation energy
What can you calculate by selecting
Born-Haber cycle?
Born-Haber cycle is useful for calculation of lattice energy, heat of
reaction and electron affinity.
How can energy change in the
formation of NACL be determined?
With the help of Born Haber’s cycle
What is the relation between
reaction taking place in one of the several stages and the total amount of
energy liberated in the reaction?
The relation between reaction taking place in one of the several stages
and the total amount of energy liberated in the reaction is same.
Define limiting
radius.
The ratio between the radius of cation and the radius of anion is called
Limiting radius.
What is Co-ordination
number?
The number of appositively charged ions surrounded a particular ion in an
ionic crystal lattice is called co- ordination number
What is structure of Nacl and give
the co-ordination number of Nacl?
The structure of Nacl is face centered Cubic and Co- ordination number of
Nacl is 6
What is the structure of cscl and
give the co-ordination number of Cscl?
The structure of cscl is Body Centered Cubic and the Co- ordination
number of CsCl is 8
Ionic compound does not show the
property of space isomerism, Give the reason?
Ionic bond is Electrostatic. It is non directional, so Ionic compounds
does not show the property of Space Isomerism
In double bond, how many sigma and
Pi bonds are present in it?
Double bond = 1 Sigma bond and one Pi bond
Among sigma and Pi bonds which is
the stronger one
Sigma bond is Stronger than pi bond
Define polar covalent
bond
The covalent bond formed by the unequal sharing of electrons between the
two atoms is called polar covalent bond.
What is dipole?
In polar covalent molecule, one atom gets positive charge and the other
one gets negative charge hence called dipole.
Covalent bond is directional
therefore which covalent property is shown?
Space Isomerism
Which theory explains the
paramagnetic nature of oxygen? Who proposed it?
Molecular orbital theory, proposed by Hunds and Mulliken
Define co-ordination covalent
bond.
Co-ordination covalent bond is formed by the mutual sharing of pair of
electrons between two atoms contributed by only one of the combining atoms.
What does one Debye
equals?
10-18 e.s.u – Cm
If a polar molecule has a charge of
4.8 * 10^ (-10) and internuclear distance is 1A then what is its dipole
moment?
4.8 * 10-10 e.s.u * 1A0
4.8 * 10-10 * 10-8
4.8 * 10-18 e.s.u – Cm
= 4.8 Debye
Give the mathematical expression to
calculate or measure the percentage of ionic Character.
% of Ionic Character = (Observed dipole moment / Dipole moment of 100%
ionic bond)*100
Who proposed VSEPR theory? What
does it explain?
VSEPR theory was proposed by Sedgwick and Powell. It explains the shapes
of polyatomic molecules.
In water molecule the bond angle
decreases from 109.28 to 104.5, why this does happens?
The repulsion between lone pair and lone pair electrons
In NH3 molecule, the bond angle
decreases from 109.28 to 107.3 why does it happen.
The more repulsion between lone pair and bond pair
Define
Hybridization.
The distribution of electrons into Hybrid orbitals is as per the Paulis
Exclusion principle and the Hunds rule of Maximum Multiplicity.
According to which rule the
distribution of electrons into hybrid orbital takes place.
The distribution of electrons into Hybrid orbitals is as per the Paulis
Exclusion principle and the Hunds rule of Maximum Multiplicity.
What is the shape of molecules SF6
and IF7?
SF6 is Octahedral
IF7 is pentagonal Bipyramidal
Give the reason why the water
molecule has high Boiling point and melting points.
Due to the presence of Hydrogen bond in water molecule
What are the units of bond length?
The intermolecular distance between the bonded atoms in a molecule is
called bond length and the units are Angstrom units (A0)
What is the order of C-H bond
length in C2H6 and C2H4 and C2H2?
c2h6>c2h4 >c2h2
Define bond angle.
The angle between the lines joining the nuclei of the bonded atom with a
central atom is called bond angle.
IN XeF4, the bond angle between
F-Xe-F is _________.
90 degrees
Define bond energy.
The amount of energy released when one mole of bonds are formed between
the corresponding gaseous atoms is called Bond energy.
Define the phenomenon
resonance.
When a molecule is represented by two or more nearly equal structures,
which differ in the arrangement of electrons, then the molecule is said to
exhibit resonance.
Which group of elements is called
alkaline earth metals?
1st A group because the oxides and hydrides are alkaline in nature
Among 1A group elements why the
element lithium is the most powerful, reducing agent in equivalent
state
Due to its low sublimation and hydration energy
Among 1A group metals the lightest
metal is_________.
Kerosene
What is the property of Alkaline
earth metal Ions?
Lithium
Which metal is more metallic in
nature among 1A group elements?
Francium
Which element in 1A group does not
form peroxides?
Lithium
Which property among the following
generally increases from top to bottom in a group 1A? 1. Electropositive,
Density, Basic nature, classical reactivity
Electropositive, Density, Basic nature, classical reactivity, and
solubility generally increase from top to bottom from lithium to caesium.
Which property among the following
generally decreases from top to bottom in a group 1A? 1. Electropositive,
Density, Basic nature, classical reactivity
Electro affinity, electro negativity, Ionisational potential, melting and
boiling points decreases from top to bottom in a group 1A from lithium to
caesium
Alkaline metals when dissolved in
ammonium (NH3) act as better conductor and better reducing agent what is the
reason behind it?
Due to formation of solvated or Ammoniated electrons
Which element in 1A group is
lighter than water?
Lithium, Sodium, and potassium
In the extraction of sodium by
cartners process the by-products formed are.
Hydrogen and Oxygen
In down’s process sodium metal is
extracted by the electrolysis of? In nelsons cell NaoH is prepared by
electrolysis of.
Electrolysis of Brime solution
What are the raw materials used for
the precipitation of Na2Co3 by Solvay ammonium Process?
Sodium Chloride, limestone and ammonia
Give the chemical formula for
Borax.
(Na2) B4 (O7) .10(H2) O
Give the formula for Peral
Ash.
The formula for Peral Ash is K2CO3.
What are the compounds used for
extraction of Gold and Silver?
NaCN and KCN
Which is the most Abundant Alkaline
earth element?
Calcium
Which is the least abundant
Alkaline earth element?
Radium
What is the Chemical formula for
Epsom salt?
MgSO4. 7H20
Why the 2A group elements are
called Alkaline earth elements?
The elements occur in earth and the oxides of these metals are basic in
nature hence the name alkaline earth metals.
Give the formula for baking
soda.
The formula for baking soda is NaHCO3.
Dolomite is the ore of which
element
Dolomite is an ore an element magnesium (mg)
Formula (MgCO3 CaCO3)
What is the name for magnesium per
chlorate and what is its formula?
Magnesium per chlorate is called Anhydrone {mg (ClO4)2}
Bleaching powder is obtained when
cl2 is passes through.
Dry Slake lime
CaOCl2+H2OàCa (OH) 2+Cl2
What is the ratio of slaked lime
and sand in mortar?
Ratio is 1:3
Which elements are present in
Electron?
Electron consist of 95 % mg, 5% Zn
Which are the most abundant metal
and third abundant element in the earth crust?
Aluminium (Al) (7.28%)
What is inert pair
effect?
The reluctances of ns electrons in the participation of bond formation is
called inert pair effect
Name the family of third ‘A’ group
elements
Boron family
In 3rd, name ‘A’ group elements which is the Non
metal
Boron
Among third A group elements which
element is best conductor?
Aluminium (Al)
Name the elements for which
Cryolite and Pelspar are the ores.
Na3 Al F6àCryolite
K2O.Al2O3.6SiO2 (or) K Al Si3
O8àFelspar
Both are ores of Aluminium
What is the process, by which
Aluminium is refined?
By Hoope’s process
Which process is used in welding
the gaps in railway tracks?
Gold Schmidt’s alumino thermi process
What does Ammonal contain? For what
purpose it is used.
It is a mixture of ammonium nitrate and aluminium powder is called
ammonal, which is used as an explosive in Bombs.
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