дано
m(KNO3) =150 g
W(прим) = 10%
--------------------------
m(HNO3)-?
m(KNO3) = 150 - (150*10%/100%) = 135 g
2KNO3+H2SO4-->K2SO4+2HNO3
M(KNO3)= 101 g/mol
n(KNO3)= m/M = 135/101= 1.33 mol
2n(KNO3) = 2n(HNO3) = 1.33 mol
M(HNO3) = 63 g/mol
m(HNO3) = n*M = 1.33 * 63 = 83.79 g
ответ 83.79 г