doubts

1)13.44 g cucl2 is dissolved in 1 kg of water. what is the elevation in boiling point?kb=0.52 kg k/mol

ans-0.16

2)which of the following statements are correct?

a)the coordination no. of each type of ion in cscl is 8.
b)metal that crystallises in bcc structure has a coordination no. of 12.
c)a unit cell of an ionic crystal shares some of its ions with other unit cells.
d)the length of the unit cell in nacl is 552pm.r+=95pm,r-=181pm

3) in a solid AB having nacl structure,A atoms occupy the corners of the cubic unit cell.if all the face-centered atoms along one of the axes are removed, then resultant stoichiometry of solid is?

3 Answers

29
govind ·

@Saket..r u sure abt that Kb value..coz the Kb for water is 0.52 ..well 134.4 is the molecular mass of CuCl2

ok in this question we need to include that vant hoff factor also..so i = 3 in this case..

Ans 2..A,C and D...
coorsination number for BCC is 8..

Ans 3...In this question just the Face centred atoms are removed so then the formula will be A3B4 ..but if all the atoms along an axis are removed then the formula will be AB...

21
amit sahoo ·

ans2) c,d.......given
ans3)ans is right but why wont it be A4B3
and yes in Q.1)kb is 0.52.......my mistake.......

29
govind ·

Ans 2..A will also be there..

Ans 3....since A atoms form the lattice and we removed Two A atoms from the two facees : ie.. one A atom is removed from the unit cell.so now the unit cell have 3 A atoms and 4 B atoms..so formula A3B4

Ans 1...molality is 0.1 and vant hoff factor = 3..this will give u the answer..

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