$C{H_3}COOH + PC{l_5} \to A\mathop {\xrightarrow{{{C_6}{H_6}}}}\limits_{anh.\,AlC{l_3}} $ $B\mathop {\xrightarrow{{{C_2}{H_5}MgBr}}}\limits_{ether} C$
$C{{H}_{3}}-C{{H}_{2}}-COOH\xrightarrow{PC{{l}_{3}}}I\xrightarrow{{{C}_{6}}{{H}_{6}}/AlC{{l}_{3}}}II\xrightarrow[\text{base/heat}]{N{{H}_{2}}-N{{H}_{2}}}III$



$(CH_3)_2CHCH_2C \equiv N \xrightarrow{HCl,{{H}_{2}}O}$ સંયોજન $A \xrightarrow[2.\,{{H}_{2}}O]{1.\,LiAl{{H}_{4}}}$ સંયોજન $B \xrightarrow[C{{H}_{2}}C{{l}_{2}}]{PCC}$ સંયોજન $C$
$(ii)$ $CH _{3} COOH$
$(iii) $ $C _{6} H _{5} COOH$
$(iv)$ $CH _{3} CH _{2} COOH$
$ PK _ {a} $ મૂલ્યનો યોગ્ય ક્રમ કયો છે ?