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

Complete the following equations: Cr₂O₇^2- + 14H⁺ + 6I →

An element with density 10 g cm⁻³ forms a cubic unit cell with edge length of 3 × 10⁻⁸ cm. What is the nature of the cubic unit cell if the atomic mass of the element is 81 g mol⁻¹?

Name the method used for the refining of zirconium.

Complete the following equation:

\[\ce{2MnO4- + 6H+ + 5NO2- ->}\]

On the basis of crystal field theory, write the electronic configuration for d⁴ ion if Δ₀ > P.

When chromite ore FeCr₂O₄ is fused with NaOH in presence of air, a yellow-coloured compound (A) is obtained, which on acidification with dilute sulphuric acid gives a compound (B). Compound (B) on reaction with KCl forms an orange coloured crystalline compound (C).

(i) Write the formulae of the compounds (A), (B) and C.

(ii) Write one use of compound (C).

Complete the following chemical equation

8MnO₄^- + 3S₂O₃^2- + H₂O →

An element crystallizes in a f.c.c. lattice with a cell edge of 250 pm. Calculate the density if 300 g of this element contains 2 × 10²⁴ atoms. 

Name the method of refining of metals such as Germanium.

Complete the following equation :

`2MnO_4^(-)+6H^++5NO_2^(-)rarr`

On the basis of crystal field theory, write the electronic configuration for d⁴ ion if ∆₀ < P.

Write the structures of main products when aniline reacts with the following reagents :

Br₂ water

Write the structures of main products when aniline reacts with the following reagents :

(CH₃CO)₂O/pyridine

What is the principle behind the zone refining of metals?

Write the chemical equations involved when aniline is treated with the following reagents:

Br₂ water

Amino acids show amphoteric behaviour. Why?

Complete the following equations : 2 MnO₂ + 4 KOH + O₂ →

Complete the following equations : 2 Na₂CrO₄ + 2 H ⁺ →​

An element with density 2.8 g cm^–3 forms a f.c.c. unit cell with edge length 4 x 10^–8 cm. Calculate the molar mass of the element.

(Given : N_A = 6.022 x 10²³ mol ^–1)

Explain the principle of the method of electrolytic refining of metals. Give one example.