Class 12th

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.

2, 4-DNP (Brady's Reagent) is used to test carbonyl compound

(a) Na₂CO₃ -> Solvay

(b) Ti -> Van-Arkel

(c) Cl₂ -> Deacon

(d) NaOH -> Castner – kellner

Kindly consider the following figure

A > B > C > D

Lone pair is localized in (A) while all 3 have delocalized lone pair but they can be compared by 3° > 2° > 1° because methyl group increases the basicity.

S > O > Se > Te   

Leaching of Al₂O₃ with alkali;

$\begin{array}{l}A{l}_2{O}_3\left(s\right)+2NaOH\left(aq\right)+3H_{2}O\left(l\right)\to 2Na\left[Al{\left(OH\right)}_4\right]\left(aq\right)\\ X\end{array}$            

$\begin{array}{l}2Na\left[Al{\left(OH\right)}_4\right]\left(aq\right)+2C{O}_2\left(g\right)\to A{l}_2{O}_3.x{H}_{2}O\left(s\right)+2NaHC{O}_3\left(aq\right)\\ XYZ\end{array}$