Advertisements
Advertisements
प्रश्न
How will you obtain pure potassium permanganate (KMnO4) crystals from its ore, pyrolusite? Give the steps involved and the reactions.
उत्तर
Potassium permanganate crystals (KMnO4) from pyrolusite:
It involves two steps
Step-1: Conversion of pyrolusite into potassium manganate
\[\ce{2MnO2 + 4KOH + O2 ->[Fuse]2K2MnO4 + 2H2O}\]
Step-2: Conversion of potassium manganate into potassium permanganate (By isolation)
\[\ce{\underset{\text{(Aqueous solution)}}{K2MnO4 + Cl2} -> 2KMnO4 + 2KCl}\]
On crystallisation, the crystals of KMnO4 appear, which are separated and dried.
APPEARS IN
संबंधित प्रश्न
Describe triclinic crystal lattice with the help of a diagram.
How will you distinguish between the following pairs of terms : Crystal lattice and unit cell
Give the significance of a ‘lattice point’.
Which of the following lattices has the highest packing efficiency (i) simple cubic (ii) body-centred cubic and (iii) hexagonal close-packed lattice?
An ionic crystal lattice has `r^+/r` radius ratio of 0.320, its coordination number is __
(a) 3
(b) 4
(c) 6
(d) 8
In the complexes `[Fe(CN)_6]^(3-)` and `[pt(en) (H_2O)_2(NO_2 (Cl)^(2+)]``the respective oxidation numbers of central metal atoms are
1) +3 and +4
2) +6 and + 4
3) +6 and +3
4) +3 and + 3
i)
Consider the following cell reaction at 298 K: [3]
2Ag+ + Cd → 2Ag + Cd2+
The standard reduction potentials (E°) for Ag+/Ag and Cd2-/Cd are 0.80 V and -0.40 V respectively:
(1) Write the cell representation.
(2) What will be the emf of the cell if the concentration of Cd2+ is 0.1M and that of Ag+ is 0.2 M?
(3) Will the cell work spontaneously for the condition given in (2) above?
(ii)
What is a buffer solution? How is it prepared? Explain the buffer action of a basic buffer with a suitable example.
Why ionic crystals are hard and brittle?
How many three-dimensional crystal lattices are possible?
AB crystallises in a body centred cubic lattice with edge length' a' equal to 387 pm The distance between two oppositely charged ions in the lattice is:
