A mixutre of Cu, Fe, and Al was reacted with 13.33 g of NaOH. During chlorination with the same amount of meta mixture entered into reaction with 12.5 L of chlorine measured at STP, while for treating the same amound of the metal mixture at STP, while for treating the same amound of the metal mix mixutre
`343.64` " mL of " HCl, havig a density of `.1g mL^(-1)` and containing `10%` by mass of HCl were required. Determine the mass percentage of the metals in the mixture.

Explanation

Out of Al, Fe, and Cu, Al reacts with NaOH.
(a). `2Al+2NaOH+10H_2Oto2Na[Al(OH)_4.H_2O]`
`1 mol` of `Al -= 1` " mol of "`NaOH`
`-=((13.33)/(40))` " mol of "`NaOH`
`-=((13.33)/(40))` " mol of "`Al`
`(13.33)/(40)xx27g of Al=9g of Al`
(b). `2Al+6"HCl"to2AlCl_3`
Cu does not react with HCl.
2 " mol of "`Al-=6 mol` of `AlCl_3`
`(9)/(27) mol =[(9)/(27)xx3]xx36.5-=36.5-=36.6 g` of HCl is used for Al
(c). `Fe+2"HCl"toFeCl_2+H_2`
(d). Total moles of HCl required to react with Al and Fe
`=MxxV_L`
Weight of `HCl=((10xx10xx1.1)/(36.5)xx(343.64)/(1000))xx36.5`
=Weight of HCl used for `Fe=37.8-36.5-=1.3g HCl`
2 " mol of "`HCl-=1` " mol of "`Fe=56 of Fe`
`((1.3)/(36.5))mol` of `HCl-=((56)/(2)xx(1.3)/(36.5))-=0.997g Fe`
All these metals reacts with with `Cl_2`
`2Fe+3Cl_2to2FeCl_3`
Volume of `Cl_2` at `STP=((3)/(2)xx(0.997)/(56))xx22.4L`
`=0.598 L` at `STP`
(v). `2Al+3Cl_2to2AlCl_3`
Volume of `Cl_2 at STP=((3)/(2)xx(9)/(27))xx22.4`
`=11.2 L` of `Cl_2`
(vi). `Cu+Cl_2toCuCl_2`
Volume of `Cl_2 at STP=(12.5-11.2-0.598)`
`=0.702 L of Cl_2`
Weight of `Cu=(0.7)/(22.4)xx63.5=1.99 g Cu`
`Al=9g,Fe=0.997,Cu=1.99g`
Total weight `=11.987g`
`%Al=75.09,%Fe=8.31,%Cu=16.6`