Chemistry

Effective no. of octahedral voids in a lattice = n

Effective no. of lattice point in a lattice = n

$$ $\therefore$  Ratio = n/n = 1

$S\left(g\right)+6F\left(g\right)\to S{F}_6\left(g\right)$

$\Delta {H^0}_R=\Delta {H^0}_f\left(S{F}_6\right)-\Delta {H^0}_f\left(S\right)-6*\Delta {H^0}_f\left(F\right)$

= (-1100) (275) 6 (80) = 1855

$\Delta {H^0}_{S-F}=\frac{1855}{6}=309.16KJ/mol\cong 309$

Beo & Be (OH)₂ are amphoteric in nature, because they react with both acid and base

Methane gas is produced during anaerobic degradation of vegetation that leads to global warming so considered as greenhouse gas like CO₂. Also it causes cancer.

For stabilization of a - helix structure of protein, H-bonding is responsible which is in between  group present in protein.

Kindly consider the following figure

During nitration of aniline, meta product is also formed, it is because of due to presence of anilinium ion. In anilium $-\stackrel{+}{N}{H}_3$ group is meta directing group.