Question

Hi!Could someone help me?

Is H2O2 (in solution , with no additives added ) basic ,neutral or acidic?What would be (theoretically) the pH of a 0.3M solution of H2O2 , considering that it reacts with water , forming the equilibrium `H_2O_2+H_2O=H_3O^{+}+HOO^{-}`

Answer 1

Very slightly acidic. `sf(pH=6.1)`

Explanation:

Set up an ICE table based on `sf("mol/l")`:

`sf(" "H_2O_2+H_2OrightleftharpoonsH_3O^++HOO^-)`

`sf(Icolor(white)(xxx)0.3color(white)(xxxxxxxxxx)0color(white)(xxxxxxx)0`

`sf(Ccolor(white)(xx)-xcolor(white)(xxxxxxxx)+xcolor(white)(xxxxx)+x)`

`sf(Ecolor(white)(x)(0.3-x)color(white)(xxxxxxxx)xcolor(white)(xxxxxxx)x`

`sf(K_a=([H_3O^+][HOO^-])/([H_2O_2])=2.4xx10^(-12))`

`:.` `sf(x^2/(0.3-x)=2.4xx10^(-12))`

Because the value of `sf(K_a)` is so small we can assume that `sf((0.3-x)rArr0.3)`.

`:.` `sf(x^2/0.3=2.4xx10^(-12))`

`sf(x=H_3O^+=8.485xx10^(-7)color(white)(x)"mol/l")`

`sf(pH=-log[H_3O^+]=-log[8.485xx10^(-7)]=6.1)`