Science (English Medium) इयत्ता १२ - CBSE Question Bank Solutions for Chemistry

Give the equations of reactions for the preparation of phenol from cumene.

Write chemical reaction for the preparation of phenol from chlorobenzene.

You are given benzene, conc. H₂SO₄ and NaOH. Write the equations for the preparation of phenol using these reagents.

Write the equation for the preparation of 1-iodobutane from but-1-ene.

How will you bring about the following conversion?

Ethane to bromoethene

How the following conversion can be carried out?

Aniline to chlorobenzene

What happens when white phosphorus is heated with concentrated NaOH solution in an inert atmosphere of CO₂?

Explain effects of lanthanoid contraction.

What are the consequences of lanthanoid contraction?

Give reasons CH₃NH₂ is more basic than C₆H₅NH₂.

An element has atomic mass 93 g mol⁻¹ and density 11.5 g cm^–3. If the edge length of its unit cell is 300 pm, identify the type of unit cell. (N_A = 6.023 × 10²³ mol⁻¹)

Calculate the number of unit cells in 8.1 g of aluminium if it crystallizes in a f.c.c. structure. (Atomic mass of Al = 27 g mol^–1)

Give reason for the following:

Red phosphorus is less reactive than white phosphorus.

Write the reaction involved in the Stephen reduction

Account for the following: 

Zn, Cd and Hg are soft metals.

Write the IUPAC name of the following coordination compound:

K₃[Fe(CN)₆]

Write the IUPAC names of the following coordination compounds: 

[CoBr₂(en)₂]⁺, (en = ethylenediamine)

Give reasons for the following :

Aquatic animals are more comfortable in the cold water than in warm water.

Write the chemical reactions involved in the process of extraction of Gold. Explain the role of dilute NaCN and Zn in this process.

Give reason (CH₃)₂NH is more basic than (CH₃)₃N in an aqueous solution.