The S Block Elements

Step 1: Recall Hückel’s rule for aromaticity.
Step 2: According to Hückel’s rule, a compound is aromatic if it is:

cyclic,
planar,
fully conjugated, and
contains electrons, where

Step 3: This rule explains the stability of aromatic compounds such as benzene, which has electrons ( ).
Step 4: Therefore, the correct statement describing Hückel’s rule is having electrons.

Step 1: Recall that a reducing agent is a substance that gets oxidised while reducing another substance.
Step 2: Examine option (C). In this reaction, silver oxide (Ag O) is reduced to metallic silver (Ag).
Step 3: Hydrogen peroxide (H O ) is oxidised to oxygen (O ).
Step 4: Since H O undergoes oxidation and causes reduction of Ag O, it acts as a reducing agent in this reaction.
Step 5: In the other options, H O acts as an oxidising agent.

Step 1: Understand what milk consists of. Milk is a mixture of fat droplets dispersed in water.
Step 2: An emulsion is a type of colloid in which one liquid is dispersed in another liquid.
Step 3: In milk, fat (liquid) is dispersed in water (liquid), forming a liquid–liquid colloid.
Step 4: Therefore, milk is an emulsion.
Step 5: The other options are incorrect because:

Suspension has large particles that settle down.
Gel is a semi-solid system.
True solution has particles of molecular size.

Step 1: Statement checks: - (A) true due to high polarizing power. - (C) true: high hydration energy. - (D) true: ammoniated electron.
Step 2: (B) isomorphic word misused; Na O is amphoteric not isomorphic → wrong. Hence → (B).

Step 1: Basic character of oxides increases down a group and is highest for alkali metal oxides.
Step 2: Identify families: - SnO – oxide of p-block metal with acidic nature. - CuO, FeO – transition metal oxides, weakly basic/amphoteric. - K O – alkali metal oxide, strongly ionic and highly basic.
Step 3: Therefore K O shows maximum basicity. Hence → (B).

Step 1: Decarboxylation reaction:
Step 2: Molar mass sodium acetate = 82 g/mol.
Step 3: 1 mole salt → 1 mole CH .
Step 4: Volume at NTP: Hence → (D).

Step 1: Recall the definitions of phase changes.

Boiling: Change of liquid into gas at a fixed (constant) temperature called the boiling point.
Evaporation: Change of liquid into gas at any temperature, occurring only at the surface.
Melting/Fusion: Change of solid into liquid.
Step 2: Analyze the given condition. The question clearly states that the change occurs at a constant temperature. Step 3: Identify the correct process. Only boiling occurs at a constant temperature. Step 4: Final conclusion. The correct answer is .

Step 1: Recall the relative basic strength of hydroxides.

Aluminium hydroxide is amphoteric and hence the weakest base.
Ammonium hydroxide is a weak base.
Magnesium hydroxide is a weak base but stronger than ammonium hydroxide.
Sodium hydroxide is a strong base.
Step 2: Arrange from weakest to strongest base. Step 3: Write the corresponding numbers. Step 4: Match with the given options. The correct option is .

Step 1: Recall carbon–carbon bond lengths in different hydrocarbons.

C–C single bond (as in C H )
C=C double bond (as in C H )
C C triple bond (as in C H )
Step 2: Nature of bonding in benzene. In benzene, all six carbon–carbon bonds are equivalent due to resonance. Each C–C bond has partial double bond character (bond order ). Step 3: Bond length in benzene. The C–C bond length in benzene is approximately: This value lies between the bond lengths of:

C–C single bond (C H )
C=C double bond (C H )
Step 4: Final conclusion. Hence, the carbon bond length in benzene lies in between C H and C H .