SRMJEEE Chemistry Mock Test - 1 - JEE MCQ

As methyl group donates electrons, hydrogen atom withdraws electrons; this makes the molecule more polarized, and it makes the molecule more reactive. Compared to acetone, acetaldehyde has less stearic effects, and other molecules can approach easily. Due to these reasons, acetaldehyde is more reactive than acetone.

The correct hydrocarbon is ethene (C₂H₄).

Ethene:

• Decolourises bromine water due to the presence of a double bond.
• Undergoes an addition reaction with bromine.
• Does not give a precipitate with ammoniacal silver nitrate because it lacks an aldehyde group (-CHO).

An aldehyde group is necessary for a positive test with Tollens' reagent.

The order of electron filling in atomic orbitals follows the Aufbau principle and Madelung rule. Electrons fill orbitals in the order of increasing n + l values, where lower n comes first for equal sums.

After argon (3p), the sequence is:

• 4s
• 3d
• 4p
• 5s
• 4d

Thus, option B correctly represents this order: 4s, 3d, 4p, 5s, 4d.

At STP, one mole of gas occupies 22.4 litres. The molecules themselves take up a minuscule fraction of this volume due to their small size relative to intermolecular distances.

• This negligible volume is less than 1%.
• This makes option B correct.

To determine which compound is aromatic, consider the following criteria:

• Planarity: The molecule must be flat, allowing for continuous overlap of p-orbitals.
• Conjugation: There should be a system of alternating single and double bonds, enabling delocalisation of electrons.
• Hückel's Rule: The molecule must contain (4n + 2) π electrons, where n is a non-negative integer (0, 1, 2, ...).

Examine each compound against these criteria to identify the aromatic one. Look for flat structures with conjugated systems and verify the π electron count to ensure compliance with Hückel's Rule.

The strength of a carboxylic acid is influenced by the electron-withdrawing effect of substituents on the α-carbon. This effect stabilises the conjugate base after deprotonation.

Among the given options:

• CF₃COOH (Option A) is the strongest acid.
• The trifluoromethyl group (-CF₃) exerts a strong electron-withdrawing inductive effect.
• This effect is due to the high electronegativity of fluorine atoms.
• The stabilisation of the negative charge on the conjugate base is more effective than with other substituents.
• As a result, CF₃COOH is more acidic than CCl₃COOH (Option D).

A carbon-carbon double bond consists of one sigma bond and one pi bond. This double bond is stronger than a single covalent bond (599 kJ/mol for C = C vs. 348 kJ/mol for C—C) and also shorter with an average bond length of 1.33 Angstroms (133 pm).

When two atoms with electrons having the same spin approach each other, orbital overlap is prevented due to electron repulsion from the Pauli exclusion principle.

Without orbital overlap:

• bonding cannot occur.

Therefore, both statements A and B are correct.

The correct relation is ΔG = ΔH - TΔS, derived from the Gibbs free energy equation. This equation helps determine a process's spontaneity:

• If ΔG is negative, the process is spontaneous at constant temperature and pressure.

The two opposite processes, forward reaction and reverse reaction, keep on occurring in it all the time but at exactly equal rates (or equal speeds)
A chemical reaction does not stop after reaching the equilibrium state, only the rate of the forward and the reverse reactions become equal at the equilibrium state

The order of a chemical reaction is determined by the mechanism of the reaction and its stoichiometry. The order is specifically based on the rate law, which depends on how the concentration of each reactant affects the reaction rate. This is experimentally determined or derived from the reaction mechanism.

While temperature and pressure can influence the rate constant and reaction progress, they do not determine the order of the reaction.

Molecularity refers to the number of reacting species in an elementary step and does not directly dictate the overall reaction order.

Soaps are classified as salts of fatty acids. They are formed during a reaction known as saponification, which involves the hydrolysis of fats (triglycerides) with a strong base or alkali, such as sodium or potassium hydroxide.

This process includes the following steps:

• Breaking down triglycerides into free fatty acids and glycerol.
• The fatty acids then combine with the alkali to form salts, which are soaps.

Soaps are typically salts of long-chain fatty acids and are classified under this category based on their chemical composition and formation process.

Key differences between soaps and detergents:

• Soaps are specifically derived from natural fats and oils.
• Detergents can be synthesized from various chemical compounds.

This distinction is important in understanding the classification and properties of soaps in chemistry.

The total number of isomers, including the stereo-isomers, with formula C₄H₇Cl is 12. Out of this, 3 are cyclic and the remaining are acyclic.

 

Ni²⁺ is paramagnetic in nature as it has unpaired electrons.

The major product from the elimination reaction is an alkene.

To determine the major alkene product, consider the following points:

• The reaction typically involves the removal of a small molecule, such as water or hydrogen halide.
• The formation of alkenes is influenced by the stability of the resulting double bond.
• More substituted alkenes are generally more stable and thus are formed preferentially.
• Identify the substituents on the carbon atoms involved in the elimination to predict which alkene is produced.

Based on these factors, the alkene with the most stable structure will be the major product. Focus on the substituents and the degree of substitution to make your final determination.

To determine if a molecule is chiral, follow these steps:

• Check each carbon atom in the molecule.
• Look for four distinct substituents attached to the carbon atom.
• If any carbon has four different groups attached, it is classified as a chiral centre.
• Consequently, the entire molecule is considered chiral.

Methyl isocyanate is a chemical compound that is produced through a reaction involving two primary substances:

• Methyl amine
• Phosgene

This synthesis process typically involves the following steps:

• Methyl amine reacts with phosgene under controlled conditions.
• The result of this reaction is methyl isocyanate, which is used in various industrial applications.

It is important to handle methyl isocyanate with care due to its toxicity and potential hazards.

When calcium acetate is heated, it undergoes decomposition but does not produce any of the listed compounds:

• Acetone
• Acetaldehyde
• Ethane
• Acetic anhydride

Therefore, none of the provided options are correct.

The phenomenon of radioactivity was first discovered by Henri Becquerel in 1896. He observed that uranium salts could emit a form of penetrating radiation that could fog photographic plates, even when the plates were wrapped and not exposed to light.

This discovery marked the beginning of research into radioactive substances, which was later advanced by scientists like Marie Curie and Pierre Curie. However, Henri Becquerel is credited with the initial discovery of radioactivity.

Carbenes are highly reactive intermediates in organic chemistry, consisting of a neutral carbon atom with two unpaired electrons and a valence of two.

• Option A is correct because carbenes can be generated by photolysis of diazomethane or ketene.
• Option B is correct as carbenes can insert into alkenes to form cycloalkanes, such as cyclopropane.
• Option C is correct since carbenes can exist in singlet (paired electrons) or triplet (unpaired electrons) states.

Since all statements A, B, and C are true, the correct answer is D, which states that all the statements are true.

Bakelite is a phenolic resin produced by the condensation polymerisation reaction between phenol and formaldehyde. This process typically occurs under heat and in the presence of a catalyst.

• Phenol
• Formaldehyde
• Condensation polymerisation: A chemical reaction where monomers combine to form a polymer, releasing small molecules such as water.
• Catalyst: A substance that increases the rate of a chemical reaction without being consumed in the process.

The key characteristics of Bakelite include:

• High durability
• Heat resistance
• Electrical insulating properties
• Ability to take on various shapes and finishes

Bakelite is widely used in:

• Electrical applications
• Household items
• Automotive parts
• Jewellery and decorative objects

Milliequivalents of NaOH = 15×1/10 = 1.5 = 0.0015 equivalents
For neutralization equivalents of acid = 0.0015
As the acid is monobasic, n factor= 1, so moles of acid required = 0.0015/1 = 0.0015
weight/MW = 0.183g/0.0015 MW
MW= 122g