1 N HCI solution means; 36.5 g of HCI are dissolved in
1000 mL. ($\because $ Equivalent wt. of HCI = 36.5)
$\therefore$ 100 mL of HCl solution contains HCl = 3.65 g
Similarly, 100 mL of HCl solution contains metal = 0.9 g
Now ,
$\frac{e wt.of \, metal}{weight \, of \, metal \, in \, solution} = \frac{ewt. of \, acid}{weight \,of \, acid \, in\, solution}$
or $\frac{ewt. of \, metal}{0.9} = \frac{36.5}{3.65}$
or E wt. of metal = $\frac{36.5}{3.65} \times 0.9 = 9 $