Explanation

Excess melanin-stimulating hormone (MSH) is secreted in Addison's disease

Because the adrenal glands are not producing enough cortisol

Which leads to an increase in ACTH (adrenocorticotropic hormone)

Which in turn stimulates the production of MSH, resulting in hyperpigmentation (darkened skin). 

Explanation

The hormone that suppresses ovulation is progesterone. 

Progesterone, particularly high levels during pregnancy, prevents ovulation by inhibiting follicular development and providing negative feedback to the hypothalamus, reducing the release of gonadotropin-releasing hormone (GnRH). 

Explanation

ADH (Antidiuretic Hormone), also known as vasopressin.

It is released by the hypothalamus in the brain and stored in the posterior pituitary gland.

ADH regulates water reabsorption in the kidneys, leading to increased water retention and decreased urine production.

Explanation

1 kilocalorie (kcal) = 4184 joules, commonly used in food energy.

1 calorie (cal) = 4.184 joules, so 1000 cal = 4184 J.

Explanation

Aldol condensation can occur between two aldehydes, two ketones, or an aldehyde and a ketone if they have at least one α-hydrogen.

The reaction forms a β-hydroxy compound, which often dehydrates to an α,β-unsaturated product.

Explanation

Nitrobenzene reacts slower than benzene in electrophilic substitution due to the electron-withdrawing nitro group.

The NO₂ group deactivates the benzene ring, making it less reactive toward electrophiles.

Explanation

Raney nickel is prepared by treating a nickel-aluminum (Ni-Al) alloy with concentrated NaOH.

This process removes aluminum, leaving behind porous nickel, which acts as an excellent hydrogenation catalyst.

Explanation

Radon (Rn) is a radioactive noble gas that is formed naturally from the decay of uranium and thorium in the Earth’s crust.

It is colorless, odorless, and radioactive.

It is often found in soil and rock.

Explanation

Silicon has the highest melting point among the given elements due to its giant covalent structure.

It requires more energy to break the strong covalent bonds.

Explanation

The S-block includes Group 1 (alkali metals) and Group 2 (alkaline earth metals) along with helium, totaling 14 elements.

These elements have their outermost electrons in the s-orbital.

Additional Information:

P-block → 6 groups (13–18) → 38 elements

D-block → Transition metals (Groups 3–12) → 40 elements

F-block → Lanthanides + Actinides → 28 elements