Explore topic-wise InterviewSolutions in Current Affairs.

Correct option is  D) Li⁺ ion

The correct answer is: (b) 10

Chromatography is a technique used to separate components of a mixture, and also purify compounds.

Principle : 

The principle of separation of substances in chromatography is based on the distribution of the solutes in two phases, i.e., stationary phase and mobile phase.

• Chromatography uses two phases for separation.
• This technique is based on the difference in rates at which components in the mixture move through the stationary phase under the influence of the mobile phase.
• In this technique, first the mixture of components is loaded at one end of the stationary phase and then the mobile phase is allowed to move over the stationary phase. The mobile phase can be a pure solvent or a mixture of solvents.
• Depending on the relative affinity of the components toward the stationary phase and mobile phase, they remain on the surface of the stationary phase or move along with the mobile phase, and gradually get separated.

Correct option is B) Al

The electronic configuration of element is 

1s² 2s² 2p⁶3s²3p⁶4s²3d³. 

[M shell electrons = 2 + 6 + 3=11]

So the element is Titanium.

B) 11, Sodium

According to the Bohr's principle of quantization of angular momentum (mvr) of a moving electron, we can write

mvr = n h/2π

Where m is the mass of the electron

v is the velocity of the electron

r is radius of the orbit

h is the Planck's constant

n is an integral number (n = 1, 2, 3,....)

The de Broglie wave length associated with the electron is given by

λ = h/mv

From the two equations, we can write

mvr/mv = {nh/2π}/{h/λ}

or, 2πr = nλ

Hence, circumference of the orbit = Integral multiple of the de Broglie wavelength.

The correct answer is: (a) ₁₅X³¹

The correct answer is: (c) 2, 8, 8

Correct option is  B) emitted

(a) For n = 4, No. of subshells = 4s, 3d, 4p.

Total no. of electrons which can be present = 2 + 10 + 6 = 18

Total no. of electrons with ms value of -1/2 = 9

(b) l = 0 describes a s-orbital. A 's' orbital can accommodate only two electrons at the most. Therefore, 2 electrons can have the quantum numbers, n = 3 and l = 0

The correct answer is: (b) Proton

1. Generally alkaline earth metals having one, two or three valence electrons prefer to lose electrons in order to get inert gas configuration. So it is difficult to add electron to alkaline earth metals. So they have positive electron gain enthalpy values. 

2. Noble gases are stable. So they do not prefer to take electrons. So they have positive electron gain enthalpy.

E = hv 

E = Energy of light 

h = Planck’s constant = 6.62 5 × 10^-27 

erg sec or 6.625 × 10^-34 Joule-sec 

v = Frequency of radiation 

This equation is called Planck’s equation.

Correct option is C) orbital

(a) The set, n = 0, l = 0, m₁ = 0 and m_s = +1/2 is not possible. This is because the quantum number n cannot have zero value.

(b) This set is possible

(c) This set is possible

(d) This set is possible

(e) This set is not possible because l cannot have a value equal to that of the n. The value of m₁, based on the wrong value of l is also not correct.

(f) This set is possible.

VIII A group or 18th group elements are called inert gases (or) Noble gases.

In Fe^3+ ion 3d sub shell is half filled hence more stable configuration.

It refers to orientation of the spin of the electron. It can have two values +1 /2 and - 1 /2. If + 1 /2 identifies the clock wise spin and - 1/2 identifies the anti- clockwise spin. The region where this probability density function reduces to zero is called nodal surfaces or simply nodes. 

(a) Not possible because n≠ 0 

(b) Not possible because when n=1, l ≠1

(c) possible 

(d) Possible

1. This gives spin of the electrons about their own axes. It is denoted by ms.

2. This quantum number refers to the two possible orientations of the spin of an electron, one clockwise and the other anticlockwise spin. 

3. These are represented by +1/2 and - 1/2. 

Correct option is a. s - orbital

When we observe spectrum of yellow light by using high resolution spectroscope it has very closely spaced doublet. Similar patterns are shown by Alkali and Alkaline earth metals. In order to account this spin quantum number is introduced.

Noble gases are highly stable.

S – orbital has two electrons.

3s; n = 3; 1 = 0; m = 0; s = + 1/2 for first electron,

n = 3; 1 = 0; m = 0; s = -1/2 for second electron.

Correct Option is : (A) n

The number of subshells in a shell is always equal to the number of shell .

Let say for nth shell - (0,1,2,.... n-1) total n, subshells are exist.

Option : (A) n

Correct Option is : (D) n and l

The energy of the orbitals depends on 'n' & 'l' quantum numbers.

Option : (D) n and l

Quicklime reacts with water vigorously to produce slaked lime and a large amount of heat.

CaO(s) + H₂O→Ca(OH)₂ + Heat

According to Bohr's Bury rule, the orbital having lower (n + l) value has lower energy.

(a) 2s, 2p

For 2s orbital, (n + l) = 2 + 0 = 2

For 2p orbital, (n + l) = 2 + 1 = 3

Since, 2s-orbital has lower (n + l) value, it has lower energy than 2p-orbital.

(b) 3p, 3d

For 3p orbital (n + l) = 3 + 1 = 4

For 3d orbital (n + l) = 3 + 2 = 5

Since, 3p, orbital has lower (n + l) value, it has lower energy than 3d-orbital.

(c) 3s, 4s

For 3s orbital (n + l) = 3 + 0 = 3

For 4s orbital (n + l) = 4 + 0 = 4

Since, 3s-orbital has value (n + l) value, it has lower energy than 4s-orbital.

(d) 4d, 5f

For 4d orbital, (n + l) = 4 + 2 = 6

For 5f orbital, (n + l) = 5 + 3 = 8

Since, 4d-orbital has lower (n + l) value, it has lower energy than 5f-orbital.

• Nashik in Maharashtra is the leading grape producer in the country as it has the soil suitable for the production of grapes.
• Glucose and fructose, the sugars present in grape juice are fermented with the help of yeast to produce wines. Therefore, wineries are located near Nashik in Maharashtra.

Microbes are observed using a microscope.

• The use of Rhizobium has helped to reduce the use of chemical fertilizers and thereby their adverse effects. 
• It has also helped to reduce expenses on fertilizers and thus benefited the farmers.

1. (i) Carbon dioxide

2. (i) Carbon dioxide

3. (i) Tartaric

4. (ii) Sodium hydrogencarbonate

5. (i) Sodium carbonate

Uses of Lactobacilli:

• Various milk products like yoghurt, buttermilk, ghee, cheese, shrikhand, etc. can be obtained by fermentation of milk. 
• Lactobacilli fermentation is useful for large scale production of cider, cocoa, pickles of vegetables etc. 
• Lactobacilli and some other useful microbes taken together are used to treat abdominal discomfort. 
• Leavened fodder offered to domestic cattle like cows and buffaloes is fodder fermented with the help of lactobacilli. 
• The Lactobacilli fermentation process is used to make wine and some types of bread.

Microbes are tiny microscopic organisms which cannot be seen with the unaided eye.

Characteristics of Microbes.

• They are the smallest organisms on earth. 
• They are composed of prokaryotic or eukaryotic cells. 
• They can be seen only with the help of a microscope. 
• They are found in any kind of environment ranging from coolest polar regions to hottest of deserts. Also found in soil, water and air.
• Some of them are useful, whereas some of them are harmful micro-organisms.

• Smear a drop of fresh buttermilk on a glass slide. 
• Stain it with methylene blue and put a coverslip over it. 
• Observe the smear under the 10X objective of a compound microscope and then with the more powerful 60X objective. 
• The blue rod-shaped organisms moving about are Lactobacilli.

• The chapatti dough has water, which on heating converts into steam and tries to escape.
• While doing so, it lifts up the upper layer of the chapatti. Therefore, the chapatti swells up.
• Bread is made by adding yeast to the flour.
• In the process of obtaining nutrition, the yeast cells convert the carbohydrates into alcohol and carbon dioxide.
• When this dough is baked, the carbon dioxide escapes out making the bread spongy, soft and easy to digest.

• Carbon compounds obtained from some bacteria and fungi for destroying or preventing the growth of harmful micro - organisms are called antibiotics.
• Antibiotics, a discovery of the 20th century, have brought a revolution in the field of medicine.
• Antibiotics mainly act against bacteria. Some antibiotics can destroy protozoa.
• Some antibiotics are useful against a wide variety of bacteria they are called broadspectrum antibiotics. Examples – Ampicillin, amoxicillin, tetracycline, etc.
• When the pathogen cannot be identified even though the symptoms of the disease are visible, broad-spectrum antibiotics are used.
• Whenever a pathogenic micro-organism is definitely known, then narrow-spectrum antibiotics are used. Examples: Penicillin, gentamycin, erythromycin, etc.

• Lactobacilli convert lactose, the sugar in the milk, into lactic acid. This process is called fermentation. 
• As a result, the pH of milk decreases causing coagulation of milk proteins.
• Thus, milk proteins are separated from other constituents of milk and milk changes into yoghurt. 
• Yoghurt has a specific sour taste due to lactic acid. The low pH destroys harmful microbes present in the milk. Therefore, Lactobacilli are used for making yoghurt from milk.

• Ethanol is a smokeless and high quality fuel. So it helps to reduce pollution when mixed with petrol or diesel. 
• As petrol or diesel is a fossil fuel less consumption of it will lead to resourceful use of it and making the country self-efficient by moving towards sustainable fuel like ethanol.

(d) Encapsulation of embryoids is done using cryoprotectant

Yoghurt, buttermilk, ghee, cheese, shrikhand, sour cream, etc.

Correct answer is: (b) alcohol and carbon dioxide

Correct Answer is: (c) Glycerol

Correct option (C) OH^-

(E)  The stronger the acid, the more positive the value of %Gº for the dissociation.