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प्रश्न
How will you distinguish between the following pair of terms?
Crystal lattice and unit cell
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उत्तर
| Crystal lattice | Unit cell |
| The three-dimensional arrangement of structural units or constituent particles (atoms, molecules or ions) in a crystal is called a space lattice or crystal lattice or simply a lattice. | Unit cell is the smallest three-dimensional group of lattice points which, when repeated in three dimensions in space, gives the whole lattice of the crystal. |
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संबंधित प्रश्न
Give the significance of a ‘lattice point’.
Calculate the number of atoms present in 2 gram of crystal which has face-centred cubic
(FCC) crystal lattice having edge length of 100 pm and density 10 gcm−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.
How will you obtain pure potassium permanganate (KMnO4) crystals from its ore, pyrolusite? Give the steps involved and the reactions.
Complete the following statement by selecting the correct alternative from the choices given:
In a face-centered cubic lattice, atom (A) occupies the comer positions and atom (B) occupies the face centre positions. If one atom of (B) is missing from one of the face-centered points, the formula of the compound is:
In a crystal of diamond:
- How many carbon atoms are present per unit cell?
- What type of lattice does diamond crystallise in?
- How many carbon atoms surround each carbon atom?
- How are they arranged?
The yellow colour in NaCl crystal is due to ____________.
Why ionic crystals are hard and brittle?
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:
How many unit cells are present in a cube-shaped ideal crystal of NaCl of mass 1.00 g? [Atomic masses: Na = 23, Cl = 35.5]
