The percentage composition `SiO_(2)` silica in the sample of clay `(Al_(2)O_(3)cdot K_(2)O cdot 6SiO_(2))` is

Options

A. `16.90%`
B. `18.35%`
C. `64.75%`
D. `25.52%`

Answer

C

Explanation

Molar mass of `Al_(2)O_(3)cdot K_(2) O cdot 6 SiO_(2)`
`=(2xx27+3xx16)+(2xx39+16)+6(28+2xx16)`
` =102+94+360`
`= 556` g
mass % of `Al_(2)O_(3)=102/556xx100 = 18.35 %`
Mass % of `K_(2) O = 94/556 xx100 = 16.90%`
Mass % of `SiO_(2) = 360/556xx 100 =64.75 %`