Aldehydes which do not contain any $\mathrm{\alpha }$-hydrogen atom shows Cannizaro's reaction , eg , HCHO , C₆H₅CHO etc

When sodium ethoxide react with ethyl bromide , it gives diethyl ether .

$\underset{\mathrm{sodium} \mathrm{ethoxide}}{{\mathrm{CH}}_3{\mathrm{CH}}_2\mathrm{O} }$ Na + Br $\underset{\mathrm{ethyl} \mathrm{bromide}}{{\mathrm{CH}}_2{\mathrm{CH}}_3}$ $\to$ CH₃CH₂OCH₂CH₃

This reaction is known as Williamson's synthesis .

When esters react with excess of Grignard reagent , 3° alcohol is formed .

Tautomerism is a special kind of functional isomerism in which the isomers exist in dynamic equilibrium with each other .It arises due to migration of hydrogen atom from one polyvalent atom to the other within the same molecule .The isomers thus obtained are called tautomers .

Thus , HCHO , CCl₃CHO and (CH₃)₃CCHO do not show tautomerism due to the absence of $\mathrm{\alpha }$ hydrogen atom w.r.t carbonyl (₂(-)C=O) group while CH₃CHO shows tautomerism as 

IUPAC name is 3-methyl-2-butenoic acid .

Structure of glucose is as 

CHO-(CHOH)₄-CH₂OH

Hence , glucose contains both aldehyde and alcohol groups .

The acidity of halogen acids depends upon the number , nature and position of halogen atom .Greater the electron withdrawing influence of halogen atom , stronger will be the acid and atoms acidic strength also increases .Thus , the increasing order of acidity is :

CH₂BrCOOH < CH₂ClCOOH < CHCl₂COCH

Chlorofonn is oxidised to poisonous phosgene in the presence of air as :

CHCl₃ + $\frac{1}{2}$O₂ $\to$ $\underset{\mathrm{phosgene}}{{\mathrm{COCl}}_2}$ + HCl

Therefore , chloroform is stored in dark coloured bottles to protect it from light .

Natural rubber is a polymer of cis-isoprene .

$$\begin{gathered} \underset{\mathrm{sucrose}}{{\mathrm{C}}_{12}{\mathrm{H}}_{22}{\mathrm{O}}_{11}} \\ [\mathrm{\alpha }{]}_{\mathrm{D}} = + 66.5° \end{gathered}$$ + H₂O $\stackrel{\mathrm{HCl}}{\to }$ $$\begin{gathered} \underset{\mathrm{D} (+) \mathrm{glucose}}{{\mathrm{C}}_6{\mathrm{H}}_{12}{\mathrm{O}}_6} \\ \left[\mathrm{\alpha }\right] = + 52.5° \end{gathered}$$ +  $$\begin{gathered} \underset{\mathrm{D} (-) \mathrm{fructose}}{{\mathrm{C}}_6{\mathrm{H}}_{22}{\mathrm{O}}_6} \\ [\mathrm{\alpha }{]}_{\mathrm{D}} = - 92.4° \end{gathered}$$

Sucrose is dextrorotatory and the resulting solution is laevorotatory with specific rotation of -39.9° because fructose has a greater specific rotation .Since , there is a change in sign from dextrorotatory to laevorotatory , the reaction is called inversion reaction and thus , sucrose (obtained from glucose and fructose) is called invert sugar .