Chemistry: CUET Mock Test - 4 - CUET MCQ

The -NHCOCH₃ group forms two resonance structures, where the lone pair of nitrogen interacts with the lone pairs on oxygen atom. This makes the lone electron pair on N less available for donation to benzene ring.

A sol is a colloidal suspension of very small solid particles in a continuous liquid medium. Sol particles typically have a charge that can be positive or negative, depending on the type of sol and the conditions of its preparation.

Among the options you provided:

• Starch - Typically, starch sols are negatively charged.
• Gum - Gum-based sols are generally not characterized by a specific charge without more context, but they are usually not particularly known for carrying a positive charge.
• Gold Sol - Gold sols are negatively charged. However, without specifying the stabilizing agent or the preparation method, we cannot definitively say it's positively charged. Historically, negatively charged gold sols are more commonly mentioned in literature due to the stabilizing agents commonly used.
• Blood is a positively charged colloid whereas sols of starch, gum & gold are negatively charged.

Correct Match of ore & its composition is :

So, correct Answer is
A - II, B - III, C - IV, D - I

Zirconium (Zr) or Titanium (Ti) is refined using van Arkel method. This method is very useful for removing all the oxygen and nitrogen present in the form of impurity in metals like Zr and Ti.

van Arkel Method for Refining Zirconium or Titanium: This method is very useful for removing all the oxygen and nitrogen present in the form of impurity in certain metals like Zr and Ti. The crude metal is heated in an evacuated vessel with iodine. The metal iodide being more covalent, volatilises:
Zr + 2I₂ → ZrI₄
The metal iodide is decomposed on a tungsten filament, electrically heated to about 1800K. The pure metal is thus deposited on the
filament.
ZrI₄ → Zr + 2I₂

Thermal stability of group-16 hydrides decreases from H₂O to H₂Po due to decrease in bond dissociation energy.

The thermal stability of hydrides decreases as we move down within a group in the periodic table. This is primarily due to the increasing size of the central atom, which weakens the bond strength between the atom and hydrogen as you move from top to bottom in a group. For group 16 (the chalcogens), water (H₂O) is an anomaly due to its unique hydrogen-bonding capabilities, making it significantly more thermally stable than other hydrides in the same group. Thus, for the given hydrides, the order from least to most thermally stable, considering periodic trends and anomalous behavior of water, would be:

So, correct order of thermal stability is H₂O > H₂S > H₂Se > H₂Te > H₂Po

A. Ammonia is produced through the Haber's process, which synthesizes ammonia from nitrogen and hydrogen gases under high pressure and temperature in the presence of a catalyst.
B. Chlorine can be produced by the Deacon process, among others, which involves the catalytic oxidation of hydrogen chloride gas into chlorine.
C. Sulphuric Acid is manufactured using the Contact process, which involves the catalytic oxidation of sulfur dioxide and its
subsequent reaction with water.
D. Nitric Acid is produced through the Ostwald's process, which involves the oxidation of ammonia to nitric oxide, followed by further oxidation to nitrogen dioxide and then absorption in water.
Therefore, the correct matches are:
A - IV: Ammonia - Haber's process
B - III: Chlorine - Deacon process
C - II: Sulphuric Acid - Contact process
D - I: Nitric Acid - Ostwald's process

On a large scale, ammonia (NH3) is manufactured by Haber’s process.
N₂ (g) + 3H₂ (g) 2NH₃(g)

While, HNO₃ is prepared using Ostwald’s method. Sulphuric acid is manufactured by contact process and Cl₂ is manufactured by Deacon’s process

The correct answer is HCL.

Key Points

• Hydrochloric acid, also known as muriatic acid, is an aqueous solution of hydrogen chloride.
• It is a colorless solution with a distinctively pungent smell.
• It is classified as a strong acid. It is a component of the gastric acid in the digestive systems of most animal species, including humans.
• Hydrochloric acid is an important laboratory reagent and industrial chemical.

Image of HCL:

Additional Information

• Nitric Acid is a strong acid with the chemical formula HNO3.
  • It is also known as the spirit of niter and aqua fortis.
  • It is colorless in its pure form, but as it gets older, it turns into a yellow cast.
  • This color appears due to the decomposition of Nitric acid to oxides of nitrogen and water.
  • It is highly corrosive and toxic.
  • It causes severe skin burns.
  • It can be manufactured by the catalytic oxidation of ammonia.
  • It is a common reagent used in laboratories and an important chemical used in industries to manufacture explosives and fertilizers.
  • The PH of Nitric acid is approximately 3.01.
  • Nitric acid molecules contain 3 oxygen atoms, 1 nitrogen atom, and 1 hydrogen atom.
• ​Chloric acid, HClO₃, is an oxoacid of chlorine, and the formal precursor of chlorate salts.
  • It is a strong acid and oxidizing agent.
• Sulfuric acid is also known as oil of vitriol because of its oily appearance.
• Formula- H2SO4.
• It is a colorless liquid.
• Used in making fertilizers, pigments, dyes, drugs, explosives, detergents, and inorganic salts and acids.

When a chemical element is present in one or more forms in the same physical state then it is known as allotrope. Swedish scientist Jons Jakob Berzelium proposed the concept of allotropes in 1841.

Ozone (O₃) is an allotrope of oxygen. It is more soluble than oxygen in the water.

Concept:

• Our periodic table as given by Moseley and has in total 7 periods running horizontally and 18 groups running vertically.
• They are also further divided into s, p, d, and f blocks depending on the placement of the outermost electrons.
• Elements belonging to the same blocks resemble in their chemical and physical properties.
• The s block elements lie in the 1st and 2nd groups.
• The p block elements belong to groups 13-18.
• The d and f block elements lie in the middle of group numbers 3-12.

Explanation:
Lanthanides:

• The lanthanides are f block elements, as they have their last electrons in 4f subshell.
• The general electronic configuration is:

​

• The lanthanides are elements having atomic numbers 58-71 from Ceriumto lutecium.
• There are 14 elements in total.
• They are called lanthanides because they resemble the element lanthanum in properties.
• They belong to period 6 but are placed at the bottom of the periodic table.
• They have stable oxidation states as +3 because two electrons are removed from the 6s and one electron from the 4f subshell.

4f-Block Elements (Lanthanides)

• Er, Tm, Tb which are Erbium, Thulium, and Terbium respectively, belong to lanthanoids.

Hence, the element that is not a lanthanoid is Pu.Additional Information

• Pu, plutonium belongs to the actinide series.
• It is radioactive in nature.
• They are also f block elements.
• The atomic number of plutonium is 94.

Actinoids: Actinoids are f-block elements starting from Th to Lr total of 14 elements. They are radioactive elements.

• They are highly reactive metals especially when finely divided.
• The 5f electrons of actinoids are poorly shielded as compared to the 4f electrons of lanthanoids. so effective nuclear charge on 5f electrons of the actinoids are more so actinoid contraction is greater.
• Lanthanoids are inner transition metals having typical metallic structures and hence good conductors of heat and electricity.
• Most of the trivalent lanthanoid ions are colored in a solid state due to the presence of f electrons.

Concept:

• Ionization energy: The energy required to remove the electron from the outermost shell of an atom or ion is called ionization energy or ionization potential.
• The energy used to remove the very first outermost electron is called the first ionization is called First ionization energy. that for removing another electron refers to second ionization energy and so on.
• Electron Volt (eV) or Kilojoules per mole (kJ/mol) are the units of ionization energy.
• Trends in the periodic table:
  • Along the period (horizontally): Along the group electrons keep adding in the same shell. Increased nuclear charge and number of electrons lead to a greater force of attraction between the nucleus and outermost electrons. Hence it requires more energy to remove the electrons from the outermost shell. Therefore ionization energy increases along the period.
  • Down the group (vertically): Down the group, the electrons start getting placed in the higher energy shells. The distance between the outermost electrons and the nucleus increases and the force of attraction between them decreases. Owing to the easier removal of electrons from the outermost shell, the ionization energy decreases down the group.

Explanation:

As we can see all the elements belong to the 2^nd period of the periodic table.
We know as we move from left to right in the period of the periodic table atomic size decrease.
The smaller the atom higher will be the ionization enthalpy. So, the Expected trend of ionization enthalpies will be, Be < B < N < O. But that is not the case here
Looking closely, we can see that Be is having fully filled and N is having a half-filled configuration as a result of which they will get some extra stability.
This extra stability is enough to elevate the ionization energy more than that of their consequent atom in the period. Hence the actual trend comes out to be B < Be < O < N.
Therefore by matching the Ionization enthalpies in the same order, the result will come out to be:- (a) → (ii), (b) → (iii), (c) → (iv), (d) → (i)
Hence, the correct option is (3).

Both ethylamine and diethylamine on reaction with CH₃CH₂Br eventually gives quaternary ammonium salt. Hence, the alkylation of primary amines cannot be used as a distinction method.

Secondary amines on reaction with Hinsberg’s reagent produce sulphonamides without any hydrogen atom attached to the nitrogen atom. Hence, it is not acidic and therefore insoluble in alkali. The amide produced in this case is N-ethyl-N-methylbenzenesulphonamide.

Secondary amines react slowly with nitrous acid at low temperatures to give yellow oily nitrosoamines. Diethylamine specifically produces N,N-diethylnitrosoamine.

Magnetic strength depends on the number of unpaired electrons possessed by the element. Iron, Cobalt, Nickel and Copper have 4, 3, 2 and 1unpaired electron respectively. Hence, the correct order of magnetic strength is: Fe > Co > Ni > Cu.

Nitrogen gas is evolved due to the decomposition of diazonium salts which are formed from the reaction of 1° aliphatic amines with HNO₂. This is used in the estimation of amino acids and proteins.

Only primary alcohols undergo oxidation in the presence of common oxidising agents followed by reaction with H₃O⁺ to give the respective carboxylic acids. This reaction is proceeded by the removal of both hydrogen atoms from the alpha carbon and formation of a double bond between C and O.

Ethyl bromide on reaction with alc. KCN gives ethyl cyanide by nucleophilic substitution. Nitriles can be hydrolysed to give amides and on further heating give a carboxylic acid which contains one more carbon than the original ethyl bromide. Hence, the acid contains three C atoms, making it propanoic acid.

Only Diamagnetic substances show a negative value of magnetic susceptibility. In the given list: oxygen and aluminium are paramagnetic, iron is ferromagnetic and nitrogen is diamagnetic. Therefore, Nitrogen has a negative value of magnetic susceptibility.

p-Xylene is a dimethyl substituted benzene which on vigorous oxidation, gets oxidised to an aromatic dicarboxylic acid, with the two carboxyl groups at para positions with respect to each other. This compound is called terephthalic acid.

Methyl magnesium bromide (Grignard reagent) on reaction with CO₂ forms an addition product containing an additional C carbon atom. This is decomposed in the presence of mineral acid to form propanoic acid.

Benzoic ethanoic anhydride (C₆H₅COOCOCH₃) is easily hydrolysed with water to give its corresponding acids, benzoic acid (by adding H to C₆H₅COO) and ethanoic acid (by adding OH to COCH₃).

Ethyl butanoate (CH₃CH₂CH₂COOC₂H₅) on basic hydrolysis forms CH₃CH₂CH₂COONa and ethanol. Then this sodium carboxylate compound gets acidified to give butanoic acid.

The Néel temperature or magnetic ordering temperature is the temperature above which an antiferromagnetic material becomes paramagnetic. The Critical temperature of a gas is the temperature above which it cannot be liquefied by pressure alone. The temperature above which a ferromagnetic substance shows no ferromagnetism is called Curie temperature.

Chromium trioxide in an aqueous solution with sulphuric acid in known as Jones reagent. It Is an important compound in the preparation of carboxylic acids from alcohols.

Aldehydes are easily oxidized to carboxylic acids having the same number of carbon atoms as the parent aldehyde, when reacted even with mild oxidising agents like Tollen’s reagent.

Amides undergo hydrolysis in the presence of heat to give corresponding carboxylic acids along with ammonia gas. In the reaction shown, benzamide undergoes oxidation to form benzoic acid.

All mono-substituted alkyl benzenes, with primary or secondary alkyl groups, on vigorous oxidation give benzoic acid. The entire side chain is oxidised irrespective of the length. In case of o-xylene, there are two methyl groups on the benzene ring and both of them are oxidised to carboxyl group, resulting in phthalic acid.

The ethyl group, acetyl group and ethene group are all oxidised to potassium carboxylate groups which are further oxidised to carboxyl groups. In the case of 4-Methylacetophenone, there are two groups that will be oxidised to carboxyl groups, hence forming terephthalic acid instead of benzoic acid.

The MgBr group of 3-Chlorophenyl magnesium bromide (Grignard reagent) will be substituted by COOH group in the above reaction, to give a halogen substituted aromatic carboxylic acid.