NEET-XII-Chemistry

Previous Year Paper year:2017

with Solutions - page 6
  • #85
    A compound is formed by cation C and
    anion A. The anions form hexagonal close
    packed (hcp) lattice and the cations occupy
    75% of octahedral voids. The formula of the
    compound is :
    (1)``C_2A_3``
    (2)``C_3A_2``
    (3) ``C_3A_4``
    (4) ``C_4A_3``
    digAnsr:   3
    Ans : ( 3 )21
    Sol. • Anions(A) are in hcp, so number of anions
    (A) = 6
    Cations(C) are in 75% O.V., so number of
    cations (C)
    =
    3
    6×
    4
    =
    18
    4
    =
    9
    2
    • So formula of compound will be
    &implies;
    9 6 9 12
    2
    C A C A
    C
    9
    A
    12
    &implies; C
    3
    A
    4