Explanation

The Rydberg constant (R_H) is used in calculating the wavelengths of hydrogen spectral lines.

Its accepted value is approximately 1.09678 × 10⁷ m⁻¹.

Explanation

CCl₄ (carbon tetrachloride) has a tetrahedral geometry with all C–Cl bonds symmetrically arranged.

The bond dipoles cancel out, resulting in no net dipole moment.

Explanation

As we move left to right in a period, the nuclear charge increases while electrons are added to the same energy level.

This pulls the electrons closer to the nucleus, so the ionic radius decreases across the period.

Explanation

The oxygen molecule (O₂) has a double bond (O=O), consisting of one sigma (σ) bond and one pi (π) bond.

The π (pi) bond is often referred to in short as a "k bond" in some notations, so O₂ contains it, unlike NH₃ or H₂O which only have σ bonds.

Explanation

The iodoform test is given by compounds having –COCH₃ group or CH₃–CH(OH)– group.

Benzophenone (C₆H₅–CO–C₆H₅) does not have a methyl group attached to the carbonyl carbon, so it does not give the iodoform test.

Explanation

Ester is formed when a carboxylic acid reacts with an alcohol in the presence of concentrated H₂SO₄ (esterification reaction).

The reaction produces ester + water as products.

Explanation

Resonance structures must have same energy level (close stability).

The pairing of electrons should follow the same scheme.

The arrangement of atoms remains the same; only electrons are delocalized.

Explanation

Aromatic compounds are rich in carbon, leading to incomplete combustion.

This results in sooty (black) flame due to unburnt carbon particles.

Explanation

Acetylene has acidic hydrogen which reacts with ammoniacal silver nitrate to form silver acetylide (Ag₂C₂).

This is a white precipitate, showing the presence of terminal alkynes.

Explanation

It reacts with Grignard reagent → gives hydrocarbon (alkane).

This happens due to the replacement of active hydrogen from –OH group.