Why do electrons have opposite spins when they are in the same orbital?

A. This condition reduces friction
B. This condition creates more energy
C. This condition results in zero magnesium and removes the change of the electron
D. This condition results in loss repulsion and opposite magnetic fields

Answer

Correct Answer: D. This condition results in loss repulsion and opposite magnetic fields

Detail about MCQs

Electrons have opposite spins when they are in the same orbital due to the Pauli Exclusion Principle, which is a fundamental principle of quantum mechanics. The Pauli Exclusion Principle states that no two electrons in an atom can have the same set of quantum numbers. In simple terms, it means that if two electrons occupy the same orbital, they must have opposite spins. This arrangement of opposite spins reduces the electrostatic repulsion between the electrons because electrons are negatively charged particles, and like charges repel each other. Having opposite spins minimizes this repulsion, leading to a more stable electron configuration for the atom. Additionally, when electrons have opposite spins, they also result in opposite magnetic fields, which is important in determining the magnetic properties of materials and is a fundamental concept in quantum mechanics.

What is the reactivity state of Phenols?

A. Less Reactive
B. More reactive
C. Neutral
D. Nonreactive

Answer

Correct Answer: B. More reactive

Detail about MCQs

Phenols are generally more reactive compared to aliphatic alcohols (alcohols with hydroxyl groups attached to aliphatic carbon chains) due to the presence of the aromatic ring (benzene ring) in their structure. The presence of the aromatic ring and the resonance stabilization it offers make phenols more acidic and more reactive towards electrophilic aromatic substitution reactions and other reactions involving the hydroxyl group. This increased reactivity is a result of the stabilizing effects of the phenyl ring on the negative charge of the oxygen atom in the phenolic hydroxyl group.

Which of the following acid can show Cis-trans isomerism?

A. Malonic Acid
B. Maleic Acid
C. Succinic Acid
D. Lactic Acid

Answer

Correct Answer: B. Maleic Acid

Detail about MCQs

Maleic acid can exhibit cis-trans isomerism because it has a double bond (C=C) in its structure, and the arrangement of substituent groups on the double bond can be cis or trans. In the cis isomer, the substituent groups are on the same side of the double bond, whereas in the trans isomer, they are on opposite sides. This cis-trans isomerism is a type of geometric isomerism seen in compounds with a double bond. The other acids mentioned (Malonic Acid, Succinic Acid, and Lactic Acid) do not have a double bond and, therefore, cannot exhibit cis-trans isomerism in the same way.

Air at sea level is dense. This is practical application of?

A. Boyles Law
B. Charles Law
C. Avogadros Law
D. Daltons Law

Answer

Correct Answer: D. Daltons Law

Detail about MCQs

Dalton’s Law of Partial Pressures states that in a mixture of gases, the total pressure is the sum of the partial pressures of individual gases. At sea level, the atmosphere is composed of various gases, with nitrogen and oxygen being the primary components. The density of the atmosphere, which is related to the pressure, is a practical application of Dalton’s Law. The total atmospheric pressure is the result of the partial pressures of these gases, making the air denser at sea level compared to higher altitudes.

The hydrocarbon which has isolated rings and is aromatic?

A. Phenanthrene
B. Triphenylmethane
C. Diphenylether
D. Anthracene

Answer

Correct Answer: D. Anthracene

Detail about MCQs

Anthracene is a polycyclic aromatic hydrocarbon with three isolated benzene rings. It is a well-known example of an aromatic hydrocarbon due to its stable, planar structure and resonance within the benzene rings, making it aromatic in nature.

When equal moles of reactant A and B are allowed to react according to the following balanced equation (2 A + B __> Product). The limiting reactant in this chemical equation will be?

A. Reactant A
B. Reactant B
C. Reactant A and B
D. No Limiting Reactant

Answer

Correct Answer: C. Reactant A and B

Detail about MCQs

To determine the limiting reactant, you need to compare the stoichiometric coefficients of the reactants in the balanced chemical equation to the initial moles of each reactant.

The balanced equation is: 2A + B -> Product

If you have equal moles of reactant A and B, this means you have a 1:1 mole ratio of A to B. In this case, neither A nor B is in excess, and they are both reacting in a 1:1 ratio as required by the equation.

So, the correct answer is: C. Reactant A and B

Both reactant A and reactant B are limiting reactants in this scenario because they are consumed in equal amounts to form the product.

Which of the following is not true about Canal rays?

A. 1.6726 x 10-27 kg
B. 9.54 x 103 C/kg
C. Show deflection under electric & magnetic fields
D. Do not cause mechanical motion

Answer

Correct Answer: D. Do not cause mechanical motion

Detail about MCQs

Canal rays, also known as positive rays, are streams of positively charged ions or cations. These ions are typically produced in a discharge tube when high-speed electrons collide with gas atoms, knocking out electrons from the atoms and leaving behind positively charged ions. Option D is incorrect because canal rays do cause mechanical motion when they collide with other particles or objects due to their kinetic energy. This motion can be used to detect and measure these rays, which was an important experimental technique in early atomic and nuclear physics research. So, option D is not true about canal rays.