Explanation

The mass of one mole of electrons is 0.55g.      

- Mass of one electron ≈ 9.109 × 10⁻³¹ kg

- 1 mole of electrons = 6.022 × 10²³ electrons

- So, mass of 1 mole of electrons ≈  

  9.109 × 10⁻³¹ kg × 6.022 × 10²³ ≈ 5.48 × 10⁻⁴ kg ≈ 0.548 g

So the correct value is about 0.55 g

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

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

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

Explanation

Metals make up the majority of elements in the periodic table, especially on the left and center.

They are generally good conductors, malleable, ductile, and have high melting points.

Explanation

Synthetic rubber like neoprene is made by the polymerization of chloroprene (C₄H₅Cl).

It is known for its resistance to oil, heat, and weathering, making it useful in industrial applications.

Explanation

As we move down Group 17 (halogens), the melting point increases due to greater molecular mass and stronger van der Waals forces.

For example: Fluorine < Chlorine < Bromine < Iodine in melting points.