Chemistry : Part I for Class XII
The Solid State - 03

Instructions

1. All questions are compulsary.
2. Please give the explanation for the answer where applicable.
3. To view the answer, click on the Answer link alongside the Question.
You can view the answer when the link becomesGreen Red. on completion of allocated time.

Q.1) A metallic element has cube lattice. Edge length of lattice cell is 2A0. The density of metal is 2.4g cm–3. How many units cell are present in 200g of metal. (3 Marks) 

Q.2) A metal oxide crystallizes in a hexagonal close packed array of oxide ions with two out of every three octahedral holes occupied by metal. Find formula of metal oxide. (3 Marks) 

Q.3) KF has NaCl structure. Its density is 2.48g cm–3. Find distance between K+ and F– ions in KF. (3 Marks) 

Q.4) The edge length of unit cell of NaCl crystal lattice is 5.6A0. The density is 2.2g cm–3. Find the number of moles of NaCl per unit cell.  (2 Marks) 

Q.5) A solid A+ B– has NaCl closed packed structure. The radius of anion is 245 pm. Find radius of anion.  (2 Marks) 

Q.6) Find the length of body diagonal of a cube having edge length of 250 pm. (2 Marks) 

Q.7) Potassium metal crystallizes in bcc. The edge length of cell is 4.3 A0. Find the radius of sodium atom.  (2 Marks) 

Q.8) What are voids? (1 Marks) 

Q.9) What happens when ferrimagnetic Fe3O4 is heated to 850 K? (1 Marks) 

Q.10) Which point defect lowers the density of a crystal?