$a.n_K=39/39=1mol$
$2K+2H_2O\to 2KOH+H_2↑$
Theo pt :
$n_{H_2}=1/2.n_K=1/2.0,1=0,5mol$
$n_{KOH}=n_K=1mol$
$⇒m_{KOH}=1.56=56g$
$m_{dd\ spu}=39+362-0,5.2=400g$
$⇒C\%_{KOH}=\dfrac{56}{400}=14\%$
$b.n_{SO_3}=200/80=2,5mol$
$m_{dd\ H_2SO_4}=1000.1,12=1120g$
$SO_3+H_2O\to H_2SO_4$
Theo pt :
$n_{H_2SO_4}=n_{SO_3}=2,5mol$
$⇒m_{H_2SO_4}=1120.17\%+2,5.98=435,4g$
$m_{dd\ spu}=200+1120=1320g$
$⇒C\%_{H_2SO_4}=\dfrac{43,5}{1320}.100\%=33\%$