Isomers of C₄H₁₀O are follows

$$\begin{gathered} \left(\mathrm{i}\right) \underset{\mathrm{butanol}-1}{{\mathrm{H}}_3\mathrm{C}-{\mathrm{CH}}_2-{\mathrm{CH}}_2-\mathrm{OH}} \\ \left(\mathrm{ii}\right) \underset{\mathrm{butanol}-2}{{\mathrm{H}}_3\mathrm{C}-\mathrm{CHOH}-{\mathrm{CH}}_2-{\mathrm{CH}}_3} \\ \left(\mathrm{iii}\right)\underset{2-\mathrm{methyl} \mathrm{propanol}-1}{ {\mathrm{CH}}_3-\mathrm{CH}\left({\mathrm{CH}}_3\right)-{\mathrm{CH}}_2-\mathrm{OH}} \end{gathered}$$

(iv) 

$$\begin{gathered} \left(\mathrm{v}\right)\underset{\mathrm{diethyl} \mathrm{ether}}{ {\mathrm{H}}_3\mathrm{C}-{\mathrm{CH}}_2-\mathrm{O}-{\mathrm{CH}}_2-{\mathrm{CH}}_3} \\ \left(\mathrm{vi}\right) \underset{\mathrm{methyl} \mathrm{isopropyl} \mathrm{ether}}{{\mathrm{H}}_3\mathrm{C}-\mathrm{O}-\mathrm{CH}{<}_{{\mathrm{CH}}_3}^{{\mathrm{CH}}_3}} \end{gathered}$$

(vii)

Hence, three isomeric ethers are possible.

Hence,  is the anhydride of 2, 3-butane diol.

An alkyl halide on heating with dry silver oxide gives ether.

$\underset{\mathrm{alkyl}\hspace{0.17em}\mathrm{halide}}{2\mathrm{R}-\mathrm{X}} + {\mathrm{Ag}}_2\mathrm{O} \underset{\mathrm{dry}}{\overset{∆}{\to }} \underset{\mathrm{ether}}{\mathrm{R} - \mathrm{O}- \mathrm{R} }+ 2\mathrm{AgX}$

In presence of NaOH or KOH, phenol reacts with alkyl halide and gives phenolic ether (C₆H₅OR).

$$\begin{gathered} {\mathrm{C}}_6{\mathrm{H}}_5\mathrm{OH} + \mathrm{NaOH} \underset{-{\mathrm{H}}_2\mathrm{O}}{\to } {\mathrm{C}}_6{\mathrm{H}}_5\mathrm{O}- \mathrm{Na} \underset{-\mathrm{NaX}}{\overset{\mathrm{RX}}{\to }} {\mathrm{C}}_6{\mathrm{H}}_{5 }-\mathrm{O}-\mathrm{R} \\ \mathrm{Vapour} \mathrm{of} {\mathrm{C}}_6{\mathrm{H}}_5\mathrm{OH} \mathrm{and} {\mathrm{CH}}_3\mathrm{OH}, \mathrm{with} \mathrm{red} \mathrm{hot} {\mathrm{ThO}}_2\left(\mathrm{thoria}\right) \mathrm{give} \mathrm{anisole} (\mathrm{phenolic} \mathrm{ether}). \\ {\mathrm{C}}_6{\mathrm{H}}_5\mathrm{OH} + {\mathrm{CH}}_3\mathrm{OH} \underset{∆}{\overset{{\mathrm{ThO}}_2}{\to }} {\mathrm{C}}_6{\mathrm{H}}_5{\mathrm{OCH}}_3 + {\mathrm{H}}_2\mathrm{O} \end{gathered}$$

Terminal alkenes react rapidly with diborane to form primary trialkyl boranes which on oxidation gives primary alcohols.

(In general hydroboration oxidation involve the addition of water according to anti-Markownikoff's rule).

When ethyl alcohol is heated with conc H₂SO₄ at 160°- 170$°$C, the product obtained is ethylene (C₂H₄).

$$\begin{gathered} {\mathrm{CH}}_3-{\mathrm{CH}}_2\mathrm{OH} + {\mathrm{H}}_2{\mathrm{SO}}_4 \to \underset{\mathrm{ethyl} \mathrm{hydrogen} \mathrm{sulphate}}{ {\mathrm{CH}}_3{\mathrm{CH}}_2{\mathrm{HSO}}_4 + {\mathrm{H}}_2}\mathrm{O} \\ {\mathrm{CH}}_3{\mathrm{CH}}_2{\mathrm{HSO}}_4 \underset{∆}{\overset{160- 170 °\mathrm{C}}{\to }} \underset{\mathrm{ethylene}}{{\mathrm{CH}}_2={\mathrm{CH}}_2} + {\mathrm{H}}_2{\mathrm{SO}}_4 \\ \mathrm{but} \mathrm{at} \mathrm{lower} \mathrm{temperature} \mathrm{ether} \mathrm{is} \mathrm{formed}. \end{gathered}$$

$({\mathrm{CH}}_3{)}_3\mathrm{CBr} + {\mathrm{H}}_2\mathrm{O} \to ({\mathrm{CH}}_3{)}_3\mathrm{C}-\mathrm{OH} + \mathrm{HBr}$

Br is substituted by OH^- (nucleophile).
S_N1 (unimolecular substitution reaction).

When sodium or potassium alkoxide is heated with an alkyl halide to give ether, this reaction is known as Williamson's synthesis.

 $\mathrm{RONa} + \mathrm{R}\text{'}\mathrm{X} \to \mathrm{R}-\mathrm{O}-\mathrm{R}\text{'} + \mathrm{NaX}$

This is an example of nucleophilic substitution and follow S_N2 mechanism.

$\underset{1-\mathrm{chlorobutane} }{{\mathrm{CH}}_3-{\mathrm{CH}}_2-{\mathrm{CH}}_2-{\mathrm{CH}}_2-\mathrm{Cl}} \underset{∆}{\overset{\mathrm{alco}, \mathrm{KOH}}{\to }} \underset{\mathrm{butene}-1}{{\mathrm{CH}}_3-{\mathrm{CH}}_2-\mathrm{CH}={\mathrm{CH}}_2} +\mathrm{HCl}$