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

The reaction,

Cr₂O₃ + 2Al → Al₂O₃ + 2Cr

 (ΔG^θ = -421kJ) is thermodynamically feasible as is apparent from the Gibbs energy value.  Why does it not take place at room temperature?

Is it true that under certain conditions, Mg can reduce SiO₂ and Si can reduce MgO? What are those conditions?

Why is the extraction of copper from pyrites more difficult than that from its oxide ore through reduction?

Write down the reactions taking place in different zones in the blast furnace during the extraction of iron.

Write chemical reactions taking place in the extraction of zinc from zinc blende.

State the role of silica in the metallurgy of copper.

The choice of a reducing agent in a particular case depends on thermodynamic factor. How far do you agree with this statement? Support your opinion with two examples.

Give evidence that [Co(NH₃)₅Cl]SO₄ and [Co(NH₃)₅SO₄]Cl are ionization isomers.

Why do we require artificial sweetening agents?

What are food preservatives?

Why is use of aspartame limited to cold foods and drinks?

What are artificial sweetening agents? Give two examples.

Name a sweetening agent used in the preparation of sweets for a diabetic patient.

What problem arises in using alitame as artificial sweetener?

Complete the following reaction:

\[\ce{C6H5NH2 + CHCl3 + alc. KOH ->}\]

Arrange the following compound in increasing order of its reactivity in nucleophilic addition reactions.

Ethanal, Propanal, Propanone, Butanone.

Hint: Consider steric effect and electronic effect.

Arrange the following compound in increasing order of its reactivity in nucleophilic addition reactions.

Benzaldehyde, p-Tolualdehyde, p-Nitrobenzaldehyde, Acetophenone.

Hint: Consider steric effect and electronic effect.

Predict the product of the following reaction:

Predict the product of the following reaction: