Chlorine can be prepared by reacting HCl with MnO2. The reaction is represented by this equation.
MnO2(s) + 4HCl(aq) → Cl2(g) + MnCl2(aq) + 2H2O(l)
Assuming the reaction goes to completion what mass of concentrated HCl solution (36.0% HCl by mass) is needed to produce 2.50 g of Cl ?
The balanced chemical equation for the reaction is:
`MnO_2(s) + 4HCl(aq)-> Cl_2(g) + MnCl_2(aq) + 2H_2O(l)`
So, `4*(35.5+1)=146 g` of `HCl` reacts with sufficient amount of `MnO_2` to produce `(35.5*2)=71 g` of chlorine.
In other words,
`71 g` of chlorine is obtained from `146 g` of `HCl` .
So, `2.50 g` of chlorine is obtained from `(146*2.50)/71=5.14 g` of `HCl`
In the conc. HCl solution,
`36 g` pure HCl is contained in `100 g HCl` solution.
So, `5.14 g HCl` is contained in `(100*5.14)/36=14.3 g HCl` solution.
Therefore, 14.3 g of conc. HCl solution is required to produce 2.50 g of chlorine.