Explanation

Elements like Cr (24), Cu (29), and Mo (42) show irregular configurations due to extra stability of half-filled or fully filled d-orbitals.

Examples:

• Cr: [Ar] 3d⁵ 4s¹
• Cu: [Ar] 3d¹⁰ 4s¹
• Mo: [Kr] 4d⁵ 5s¹

Explanation

The cochlea is a spiral, snail-shaped structure in the inner ear responsible for converting sound vibrations into nerve signals.

It plays a key role in the sense of hearing.

Explanation

To find the equilibrium constant (Kc) for the reaction H₂ (g) + I₂ (g) ⇌ 2HI (g), we use the formula:

Kc = [HI]² / [H₂] [I₂]

Given concentrations:

[HI] = 0.08 mol/dm³

[H₂] = 0.04 mol/dm³

[I₂] = 0.04 mol/dm³

Kc = (0.08)² / (0.04 × 0.04)

= 0.0064 / 0.0016

= 4

Explanation

Kala azar (also known as visceral leishmaniasis) is caused by the protozoan parasite Leishmania donovani.

It is transmitted to humans by the bite of infected female sandflies.

Explanation

Diffusion is the process where particles move from an area of high concentration to low concentration.

Ink spreads evenly in water due to molecular motion, resulting in uniform distribution.

Explanation

Optimum Temperature is the specific temperature at which an enzyme exhibits peak catalytic activity.

Deviations (higher/lower) reduce efficiency, as enzymes are temperature-sensitive proteins.

Explanation

Freons (CFCs) and halons are stable in the troposphere but break down under UV light in the stratosphere.

This breakdown releases chlorine and bromine, which destroy ozone molecules in the ozone layer.

Explanation

Modern psychologists focus on the value of satisfaction as a motivator in the learning process.

Satisfaction enhances retention and engagement in learners.

Explanation

The true aim of education is holistic development — gaining practical skills, positive habits, and useful knowledge.

It focuses on preparing individuals for life, not just exams or jobs.

Explanation

A covalent bond forms when two non-metals share electrons.

This type of bond results in the formation of molecules like H₂O and CO₂.