M(OH)62− is formed when  hot or cold NaOH reacts  with  M  , where M is

Sn and Pb are slowly attacked by cold alkali and rapidly by hot alkali giving sodium stannate Na2Sn(OH)6and sodium plumbates Na2Pb(OH)6Si reacts slowly with cold aqueous NaOH solution and readily with hot solution forming SiO42−.Ge does not react.