Question

$C{O}_2$ is a gas, while $Si{O}_2$ is a solid but both are:

• A. covalent containing $\pi$ -bond
• B. molecules having $p\pi$ - $d\pi$ bonding
• C. acidic
• D. discrete molecules

Answer 1

Answer: (C)

acidic

• $C{O}_2$ consists of individual molecules with one central carbon atom double bonded to two oxygen atoms. Silicon does not form double bonds with oxygen. $C{O}_2$ is gas but $Si{O}_2$ is solid because the $Si{O}_2$ is in giant molecular structure but the $C{O}_2$ is simple molecular structure.because of this reason $C{O}_2$ is gas but $Si{O}_2$ is solid.
  
• $C{O}_2$ is an acidic oxide can be explained by Lux-Flood concept & extended Lewis theory. $C{O}_2$ with $H_{2}O$ produces $H_{2}C{O}_3$ i.e. carbonic acid.
  
• Silicon dioxide has no basic properties - it doesn't contain oxide ions and it doesn't react with acids. Instead, it is very weakly acidic, reacting with strong bases. Silicon dioxide doesn't react with water, because of the difficulty of breaking up the giant covalent structure.