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2 or TWO

Detailed Answer :

In K₂MnO₄ Oxidation state be (x).

pH = – log [M] = – log (0.01) = – log (10^–2) = 2

The ideal gas equation for one mole of a gas PV = RT.

The SI unit of amount of substance mole.

The energy required to form the intermediate called activated complex is known as activation energy. Activation energy = Threshold energy – Average energy of the reactants

Reverse osmosis: If a pressure larger than the osmotic pressure is applied on the solution side, the solvent starts to flow from the solution into the pure solvent through the semipermeable membrane.
This phenomenon is called reverse osmosis.

k (conductivity) = 1/ R(Resistance) x G (Cell constant)

If either the ore or the gangue is capable of being attracted by magnetic field, then such separation are carried out by magnetic separation.

(i) Pig iron is melt with scrap iron and coke using hot air blast. Due to this, impurities such as C, S and P present in the pig iron are removed as CO₂, SO₂ and P₂O₅ and carbon content reduced to about 3%.

(ii) Bauxite is soluble in concentrated NaOH solution whereas impurities are not.

Molarity is the number of moles of solute dissolved in one litre of solution whereas molality is the number of moles of solute per kilogram of the solvent. Molarity decreases with increase in temperature as volume increases with increase in temperature. Molality is independent of temperature because mass does not depend on temperature.

The four bases present in DNA are adenine (A), guanine (G), cytosine(C) and thymine (T). Thymine(T) is not present in RNA.

Molality is the number of moles of solute per thousand grams of solvent whereas molarity is the number of moles of solute dissolved in one litre of solution. Molality is independent of temperature whereas molarity changes with change in temperature as volume changes with temperature.

(i) Elementary step: Each step of a complex reaction is called an elementary step.
(ii) Rate of reaction: It is the change in the concentration of any of the reactants or products per unit time.

The two monomers (adipic acid and hexamethylene diamine) contain 6 carbon atoms each.

This is due to polymeric structure of red phosphorus or angular strain in P₄ molecule of white phosphorus where the angle is only 60°.

NH₃ < (CH₃)₃N < CH₃—NH₂ < (CH₃)₂ NH.

(a) p-type, because In has 3 valence electrons. Holes are produced which can move through the crystal like positive charge. 

(b) n-type, because P has 5 valence electrons. The fifth electron becomes delocalised and is free contribute to electrical conduction.

Conducting can be defined as the tendency of the solution to conduct electricity and conductance of all the ions present in 1cm³ of solution which is present between electrodes present 1cm apart and area of electrode is such that whole solution is present between them-

Molar conducting can be defined as conductance of all the ions present in Vcm³ of solution containing 1mol electrolyte and solution is kept between electrodes present 1cm apart and area of electrode is such that it contain whole solution between them units of specific conductivity 

K = Scm^–1 

molar conductivity 

Λ_m = Scm² mol⁻¹

(B) Two of the three statements are true.

Alkali metals are highly reactive due to their very low ionisation energy. So, alkali metals are not found in free state.

Hund’s Rule of Maximum Multiplicity- It states that pairing of electrons in the orbitals belonging to the same subshell (p, d or f) does not take place until each orbital belonging to that subshell has got one electron each i.e. it is singly occupied.

(i) efficient, 74

(ii) increase, decrease

(iii) distorted octahedral, sp³d³

(iv) greater than, less than

Uses of Hydrogen Peroxide-

(i) It is used as a hair bleach and as a mild disinfectant.

(ii) It is used in the synthesis of hydroquinone, tartaric acid etc.

Correct Option

 (2) – 0.372°C

(i) Invert Sugar: Sucrose is dextrorotatory, on hydrolysis in the presence of HCl or enzyme invertase, it produces a mixture of D–C(+)–glucose and D–(–)–fructose which is laevorotatory called invert sugar.

(ii) Polypeptide: If more than ten a-amino acids are joined together by peptide bond (–CONH–) the polyamide thus formed is called polypeptide.

Correct Option (4) CH₃ – Br

Correct Option 

(2) Secondary alcohol

Correct Option (3) Zinc blende

(a) In beryllium [z = 4, 1s², 2s²], the electron removed during the ionization is an s-electron while the electron removed during ionization of boron (Z = 5, 1s²,2s²,2p¹) is a p-electron.

The penetration of a 2s electron to the nucleus is more than that of a 2p-electron , so the 2p electron of boron is more shielded from the nucleus by the inner core of electrons than the 2s electrons of beryllium. Hence, it is easier to remove the 2p- electrons from boron compared to the removal of 2s electron from beryllium. Hence, first ionization enthalpy of boron (Z =5) is slightly less than that of beryllium (Z= 4).

(b) Electron gain enthalpy of fluorine is less negative than that of chlorine because when an electron is added to F, the added electron goes to the smaller n = 2 quantum level and suffers significant repulsion from the other electrons present in this level. While for the n=3 quantum level (Cl), the added electron occupies a larger region of space and the electron-electron repulsion is much less.  

(c) Size of an anion is always larger than that of parent atom because the addition of one or more electrons would result in increased repulsion among the electrons and a decrease in effective nuclear charge.

(i) Disaccharide–Sucrose

(ii) Artheneus equation–Activation energy

(iii) Dacron–Condensation polymer.

(iv) Freundlich isotherm–Adsorption

(a) The stability of a particular oxidation state depends upon the nature of the element with which the transition metal forms the compound. Mn forms a stable oxide Mn₂O₇. This is probably due to the ability of the oxygen to form multiple bond in the oxides.

(b) Cr⁺² = [Ar] 4s⁰3d⁴

Mn⁺³ = [Ar]4s⁰3d⁴

For Cr, +3 oxidation state is more common

Thermo setting

(1) Highly branched or cross bonded

(2) Recycling is not possible

Thermo plastic

(1) Less branched and cross bonds are absent

(2) Recycling is possible

Zeolite is shape selective catalyst. In these catalyst pores are present which adsorb substance according to its shape and size.

Let √2 be a rational number. 

∴ √2 = a/b , (a, b are co-prime integers and b ≠ 0) 

a = √2 b 

Squaring, a² = 2b² 

⇒ 2 divides a² 

⇒ 2 divides a. 

So we can write a = 2c for some integer c, substitute for a, 2b² = 4c² , b² = 2c² 

This means 2 divides b² , so 2 divides b. 

∴ a and b have ‘2’ as a common factor. 

But this contradicts that a, b have no common factor other than 1. 

∴ Our assumption is wrong. 

Hence, √2 is irrational. 

Let 3/√2 be rational

3/√2 = a/b , where a and b are integers, b ≠ 0

3b = √2a

√2 = 3b/a

3b/a is rational but √2 is not rational.

∴ Our assumption is wrong. 

∴ 3/√2 is irrational.

Total number of outcomes = 100 

(i) P (single digit number) = 9/100

(ii) P (perfect square) = 10/100 = 1/10

(iii) P (a number which is divisible by 7) = 14/100 = 7/50

x²-(a²-1)/a.x-1

=x²-ax+1/a.x-a/a

=x(x-a)+1/a(x-a)

=(x-a)(x+1/a)

x⁶ – y⁶ 

= (x³)² – (y³)² 

= (x³ + y³)(x³ – y³),

= (x + y)(x² – xy + y²)(x - y)(x² +xy +y²),

(i) communication has become effective / instant message all around the globe without spending hefty sums

(ii) — able to broaden their minds and improve their skills by doing research on the internet

— help in online learning,

— help look up new word they come across

— help complete assignments on time

— provide online teaching (any four each half mark)

(iii) Can help in any emergency prevent crimes by providing information on to security

(iv) Adverse impacts / affects academic performance can lead to addiction / waste of time/ misuse get involved in undesirable activities (any two)

(v) Allows subscribers to load text / airtime credits to their handsets it doesn't commit a particular customer to a contract one can opt to subscribe using the pay by monthly plan

Detailed Answer : 

(i) The smart phones are helpful in communication because with the access of smart phones, communication has become very effective and instant. People are able to convey their message all round the globe to their loved ones without spending hefty sums of money. 

(ii) Smart phones are helpful for the young generation as people are able to tour the cosmos virtually sitting at one place using their smart devices or other technological gadgets. 

(iii) Mobile phones can be considered 'life savers' because lot of people use them in case of emergency. 

(iv) The two demerits of mobile phones are : 

(a) Mobile phones can be like an addiction and the young people can misuse it. 

(b) Young people are prone to getting involved in undesirable activities on the Internet. 

(v) A prepaid card is useful to mobile phone users as it allows subscribers to load text or airtime credits to their handsets by the use of their credit cards, debit cards or by buying a prepaid card from the network they subscribe to.

Title & Moral - 1 mark

Content - 4 marks

Expression 5 marks (coherence, relevance of ideas) 

(Accuracy, appropriate words and correct spellings

Suggested value points:(Hints given in the question)

Detailed Answer : 

This is the story of two friends tortoise and hare. Both the tortoise and hare were fast friends. Wherever they went, they went together. The only difference between them was that tortoise had a slow speed while the hare had a fast speed. Sometimes they both started to work or to go somewhere at same time but due to his slow speed, the tortoise was always late while the hare did the work at a fast speed. Thus, the hare sometimes made fun of his friend tortoise but the tortoise neglected the hare's attitude. Inspite of being fast friends, they sometimes had petty issues over their speed. The Tortoise told his friend that slow speed is not a curse but a boon but the hare never stopped himself from making fun of his friend. One day the Tortoise got frustrated and threw a bold challenge to the hare to have a race. It was decided that one who reached the river bank first would be the winner. They selected their referee and at a fixed time the race started. The hare ran at a fast speed and was miles ahead of the tortoise. He turned back and saw that his friend tortoise was not visible far and wide. Then he decided to have a rest because according to him, the tortoise would take a long time to reach him. He was over confidant of his winning so he lay down and fell asleep. The tortoise continued walking. On his way, he saw the hare sleeping but he didn't stop and he reached the river bank. When the hare got up, he looked around for the tortoise. Then he started his race at a double speed but found that the tortoise had already reached the river bank. In this way tortoise won the race. Moral : Slow and steady wins the race.

(i) — (iii) invention 

(ii) — (ii) emails 

(iii) — (iii) monitor

(iv) — (ii) negative 

(v) — (ii) monthly

India.gov.in

URL: India.gov.in

(i) WAN

(ii) LAN

They are not exactly the same. Boiling of liquid takes place at its boiling point, whereas evaporation can occur at any temperature or room temperature. Evaporation is a surface phonemenon while boiling is a bulk phenomenon.

Genetically modified crop: In this method, a gene that would provide the desired characteristics is introduced into the crop. The crop so obtained is called genetically modified crop.

Some of the factors for which crop variety improvement is done are:

1. Higher Yield: Variety improvement has been done to increase the productivity of the crop per acre of cultivated land. This is very important in order to meet the food demand for rapidly growing population.
2. Improved Quality: The definition of quality is different for different crops, e.g. baking quality is important in wheat, protein quality in pulses, oil quality in oil seeds and preserving qualities in fruits and vegetable.
3. Wider Adaptability: Varieties that can grow under any condition and can adapt themselves to various environmental conditions, help in stabilising the crop production.
4. Biotic and Abiotic Resistance: Biotic factors like (pathogens, insects and nematodes) and abiotic factors (drought, salinity, water logging, heat cold and frost) affects crop production to a great extent. Varieties resistant to such factors are always preferred and improves the crop production.

Two ways to control weeds:

1. Preventive methods: Proper seed bed preparation, timely sowing of crops, intercropping and crop rotation.
2. Chemical methods: Spraying of herbicides or weedicides, e.g. Atrazine 2, 4 – D.

It is the tendency of a body to remain in its state of rest or of uniform motion in a straight line. Quantity that measure it is mass.

f=m × a;     5 × 6 = 30 N
f= m × a;    6 × 5 = 30 N
Both the objects will exert the same force.