$Sn{O_2} + 2{H_2}S{O_4} \to Sn{\left( {S{O_4}} \right)_2} + 2{H_2}O$
$Sn{O_2} + 2NaO{H_4} \to N{a_2}Sn{O_3} + 2{H_2}O$