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The manufacture of K₂Cr₂O₇ from chromite ore involves is steps. 

Step-1: 4FeCr₂O₄ + 8Na₂CO₃ + 7O₂ → 8Na₂CrO₄ + 2FerO₃ + 8CO₂ 

Step-2: 2Na₂CrO₄ + 2H⁺ → Na₂Cr₂O₇ + 2Na⁺ + H₂O 

Step-3: Na₂Cr₂O₇ + 2KCl → K₂Cr₂O₇ + 2NaCl

(i) a. Corrosion: 

Corrosion is a natural process, which converts a refined metal to a more stable form, such as its oxide or hydroxide. It is the gradual destruction of metals by chemical reaction with their environment. Rusting, the formation of iron oxides is a well-known example of electro-chemical corrosion. 

b. Rancidity: 

Rancidity refers to the spoilage of food in such a way that it becomes undesirable and unsafe for consumption. It is the hydrolysis or autoxidation of fats into short chain aldehydes and ketones which are objectionable in taste and odour. When rancidity occurs in food, undesirable odour and flavours can result. In some cases, however, the flavours can be desirable (as in aged cheeses). 

(ii) Noble metals such as gold and platinum do not corrode easily.

Fe²⁺ ion has electric configuration (Ar)4S⁰3d⁶ it has four paired electrons 

∴ n = 4 

spin only magnetic moment μ = \(\sqrt{n(n+2)}BM\)

= \(\sqrt{4(4+2)}BM\) 

= \(\sqrt{24}BM\) 

= 4.9BM

d-block elements form co-ordination compounds. 

Reasons: 

(i) They are small size of metals ions 

(ii) They have high ionic charges, 

(iii) Availability of d-orbitals

NH₃ + Cl₂(excess) → NCl₃ + 3HCl

The importance of forests cannot be underestimated. We depend on forests for our survival, from the air we breathe to the wood we use. Besides providing habitats for animals and livelihoods for humans, forests also offer watershed protection, prevent soil erosion and mitigate climate change.

Chlorine is prepared by heating MnO₂ with con HCl. 

MnO₂ + 4HCl → MnCl₂ + Cl₂ + 2H₂O

Because interhalogen compounds are more reactive than halogens the bond between atoms in inter halogens (x – x¹) is weaker than the bond in halogens (x – x) hence ICl is more reactive than I₂.

a. When thin copper leaves are thrown in a jar of chlorine they catch fire and form cupric chloride.

Cu (Copper) + Cl₂ (Chlorine) → CuCl₂ (Cupric chloride)

b. 1. Due to greater electronegativity of O than S, H₂O undergoes extensive intermolecular H-bonding. As a result, H₂O exists as an associated molecule in which each O is tetrahedrally surrounded by four water molecules. Large amount of energy is required to break these H-bonds. Therefore, H₂O is a liquid at room temperature. 

2. In contrast, H₂S does not undergo H-bonding. It exists as discrete molecules which are held together by weak van der Waals forces of attraction. To break these forces of attraction, only a small amount of energy is required. Therefore, H₂S is a gas at room temperature.

c. Given: C = 0.02 M , k = 2.428 x 10^-3  Ω^-1 cm^-1 

To find: Molar conductivity 

Formula: Molar conductivity = \(\frac{1000k}{C}\) 

Calculation: Molar conductivity = \(\frac{1000k}{C}\) = \(\frac{1000\times2.428\times10^{-3}}{0.02}\)

= 121.4 Ω^-1 cm² mol^-1

d. Henry’s law relates solubility of a gas with external pressure. The law states that, “the solubility of a gas in liquid at constant temperature is proportional to the pressure of the gas above the solution”.

Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion

By the action of HCl on KMnO₄. 

2KMnO₄ + 16HCl → 2KCl + 2MnCl₂ + 8H₂O + 5Cl₂.

PbS + 4O₃ → PbSO₄ + 4O₂ 

Cu + 2H₂SO₄ → CuSO₄ + SO₂ + 2H₂O 

Cl₂ + 2H₂O + SO₂ → H₂SO₄ + 2HCl

1. The bauxite ore contains silica (SiO₂) Iron oxide (Fe₂O₃) and titanium dioxide (TiO₂) as impurities. Bauxite in concentrated by digesting the powdered ore in a concentrated solution of NaOH at 473–523K and 35 bar pressure. Al₂O₃ dissolves in alkali and is leached as sodium aluminate leaving impurities behind. 

2. The solution of Sodium aluminate is filtered cooled and neutralised by passing CO₂ gas and hydrated Al₂O₃ is precipitated by seeding. 

3. Hydrated alumina is filtereds dried and heated to get pure alumina (Al₂O₃).

a) CH₄ + 2O₂ → CO₂ + 2H₂O

b) 2Fe³⁺ + SO₂ + 2H₂O → 2Fe²⁺ + SO^2-₄ + 4H⁺

c) C₁₂H₂₂O₁₁ \(\overset{conc.H_2SO_4}{\longrightarrow}\) 12C + 11H₂O

Ostwald process to manufacture nitric acid-

Catalytic oxidation of Ammonia

A mixture of dry air and dry ammonia in the ratio of 10:1 by volume is compressed and then passed into a platinum gauze which acts as catalyst at about 800℃.

4NH₃​ + 5O_2​⟶4NO+6H₂​O + Heat

Ammonia gas can be manufactured, on large scale, by Haber's process. Which can be used as a source of NH₃ in manufacture of Nitric oxide.

N₂(g) + 3H₂(g) \(\rightleftharpoons\) 2NH₃(g)

3, 7-Dimethylocta-2, 6 dien-1-al

Answer is:

(C) +5

(B) disaccharide

(D) 36

In ferrocyanide ion, [Fe(CN)₆]^4– 

Fe \(\overset{-2e^-}\longrightarrow\) Fe²⁺ + 6CN^– → [Fe(CN)₆]^4– 

Formula : for EAN = Z – X + Y

 Here, Z = atomic number of iron = 26. 

X = number of electrons lost due to oxidation of Fe to Fe²⁺ = 2. 

Y = number of electrons donated by 6CN^– = 6 x 2 = 12.

∴ EAN = 26 – 2 + 12 = 36

(B) diethyl ether and ethanol

Natalite is used as fuel.

(i) Higher pk_b means, lower is the basic character i.e aniline is weaker base than methyl amine. In aniline lone pair of electron on nitrogen atom is delocalized over the benzene ring due to the resonance effect. As a result electron density on nitrogen atom decrease. In methylamine due to +I effect electron density on nitrogen atom increase. 

(ii) Aniline does not undergo Friedel‐Crafts reaction due to salt formation with aluminium chloride. 

(iii) Gabriel phthalimide reaction gives pure 1° amines.

Given, 

M = 93 g mol^-1 

d = 11.5 g cm^-3 

a = 300 pm = 300 x 10^-10 cm = 3 x 10^-8 

We know that,

d = \(\frac{z\times M}{N_A\times a^3}\) 

z = \(\frac{d\times N_A\times a^3}{M}\) = \(\frac{11.5\times6.022\times10^{23}(3\times10^{-8})^3}{93}\) 

= 2.01

The number of atoms present in given unit cells is coming nearly equal to 2. Hence, the given unit cell is body centred cubic unit cell (BCC).

A - C₆H₅CHO, 

B - C₆H₅COONa 

C - C₆H₅CH₂OH, 

D -C₆H₅CH = NNHCONH₂, 

E -C₆H₅CH(OH)CH₃ 

(i) CH₃CH(CN)OH 

(ii) CH₃CH(OH)CH₂CH₃ 

(iii) CH₃CH₃ 

(b) Ethanal > Propanal > Propanone > Butanone 

(c) Propanal gives red ‐brown ppt with Fehling’s reagent / Propanal givessilver mirror test but propanone does not react both of these reagents.

(A) Cr²⁺ is a reducing agent 

(B) Mn³⁺ is an oxidizing agent 

(C) Both Cr²⁺ and Mn³⁺ exhibit d⁴ electronic configuration 

(1) Cr²⁺ is a reducing agent because Cr³⁺ is more stable. 

(2) Mn³⁺ is an oxidizing agent because Mn²⁺ is more stable. 

(3) Cr²⁺ and Mn³⁺ exhibit d⁴ electronic configuration.

Answer: D) Sodium Chloride

Since X is a colorless solution, it does not contain transition metal ions. The white ppt is likely to be AgCl.

Lime water turns milky or white Ca(OH)₂ + CO₂ → CaCO₃ + H₂O

No, Cl - 35 and Cl - 37 will be placed in same slot. The modem periodic table is based on atomic numbers not atomic mass since, both Cl - 35 and Cl - 37 have same atomic numbers hence they are placed in same slot.

In the periodic table elements are placed according to their atomic number. If an element has only one shell in its electronic configuration it is placed in the first period, if the element has two shells then it is placed in the second period and so on. Vertical column in the periodic table are called groups there are eighteen groups and in a group all the elements have same number of valence electron.

a) Derive economic needs from primary activities

(a) Environmental Determinism

The position of elements depend upon number of valence electrons which depend upon electronic configuration those elements which have same valence electrons occupy same group. Those elements which have one valence electrons belong to group 1 elements, which have two valence electrons belong to group 2. Period numbers is equal to the number of shell.

Example: atomic number of sodium (Na) is 11, so electronic configuration will be 2, 8, 1. Sodium has one valence electron in valence shell so it belong to group 1 as sodium has three shells, so it belong to 3rd period.

“Properties of elements are the periodic function of their atomic number”.

The 9 Parts of Speech:

Noun

Nouns are a person, place, thing, or idea. They can take on a myriad of roles in a sentence, from the subject of it all to the object of an action. They are capitalized when they're the official name of something or someone, called proper nouns in these cases. Examples: pirate, Caribbean, ship, freedom, Captain Jack Sparrow.

Pronoun

Pronouns stand in for nouns in a sentence. They are more generic versions of nouns that refer only to people. Examples:​ I, you, he, she, it, ours, them, who, which, anybody, ourselves.

Verb

Verbs are action words that tell what happens in a sentence. They can also show a sentence subject's state of being (is, was). Verbs change form based on tense (present, past) and count distinction (singular or plural). Examples: sing, dance, believes, seemed, finish, eat, drink, be, became

Adjective

Adjectives describe nouns and pronouns. They specify which one, how much, what kind, and more. Adjectives allow readers and listeners to use their senses to imagine something more clearly. Examples: hot, lazy, funny, unique, bright, beautiful, poor, smooth.

Adverb

Adverbs describe verbs, adjectives, and even other adverbs. They specify when, where, how, and why something happened and to what extent or how often. Examples: softly, lazily, often, only, hopefully, softly, sometimes.

Preposition

Prepositions show spacial, temporal, and role relations between a noun or pronoun and the other words in a sentence. They come at the start of a prepositional phrase, which contains a preposition and its object. Examples: up, over, against, by, for, into, close to, out of, apart from.

Conjunction

Conjunctions join words, phrases, and clauses in a sentence. There are coordinating, subordinating, and correlative conjunctions. Examples: and, but, or, so, yet, with.

Articles and Determiners

Articles and determiners function like adjectives by modifying nouns, but they are different than adjectives in that they are necessary for a sentence to have proper syntax. Articles and determiners specify and identify nouns, and there are indefinite and definite articles. Examples: articles: a, an, the; determiners: these, that, those, enough, much, few, which, what.

Interjection

Interjections are expressions that can stand on their own or be contained within sentences. These words and phrases often carry strong emotions and convey reactions. Examples: ah, whoops, ouch, yabba dabba do!

Correct Option (d) The reaction yields three other condensation products besides X

Explanation:

The reaction will yield only one or two condensation products because C₆H₅CHO does not contain any α - hydrogen atom compound Y is

C₆H₅ - CH = CH - CHO.

Magnesium (Mg) → [Ne] 3s²

Scandium (Sc) → [Ar] 3d¹ 4s² 

Nitrogen (N) → [He] 2s² 2p³