Which of the following small-sized elements can repalce silicon and aluminium in the framework at zeolites
a. Boron
b. Magnesium
c. Phosphorus
d. All
ii. Zeolites are microporous aluminosilicates with general formula
a. `M[(AlO_(2))_(x)].mH_(2)O`
b. `M_(x)[AlO_(2))_(x)(SiO_(2))_(y)]`
c. `M_(x)[(SiO_(2))_(y)].mH_(2)O`
d. `M_(x//n)[(AlO_(2))_(x)(SiO_(2))_(y)(SiO_(2))_(y)].mH_(2)O`
iii. The zeolites have shape selectivity depending on
a. Pore structure
b. Atomic structure
C. Molecular structure
d. None