Question

Silica is a network solid with $Si-O-Si$ bonds. In many aluminosilicates, a few $Si$ atoms in the silica structure are replaced by $Al$ atoms. Zeolites, clays, asbestos etc. are examples of aluminosilicates having different structures. The statement which is not correct is:

• A. The basic structural unit in silicates is tetrahedral $(Si{O}_4{)}^{4-}$
• B. Replacement of a $Si$ atom in silica by an $Al$ atoms results in negative charge on the $Al$ atom
• C. Silica dissolves in aqueous $NaOH$ to form sodium silicate in which $N{a}^{+}$ is bonded to oxyanions
• D. Silicones are examples of silicates

Answer 1

Answer: (D)

Silicones are examples of silicates

Silicones are different than silicates. Silicones are synthetic organosilicon compounds containing repeated $R_{2}SiO$ units held by $Si-O-Si$ linkage. Silicones have empirical formula $R_{2}SiO$. Silicates are made up of $Si{O}_4^{4-}$ tetrahedral units. Silicon is $s{p}^3$ hybridised and surrounded by 4 oxygen atoms.