A chemical change affects on the molecular level of matter, which makes it irreversible. Combustion is a pretty good exmple. Physical changes are reversible and dont alter the formula. Hope this helped!
Answer : The pH of the solution is, 9.63
Explanation : Given,
The dissociation constant for HCN = 
First we have to calculate the moles of HCN and NaCN.

and,

The balanced chemical reaction is:

Initial moles 0.1116 0.0461 0.08978
At eqm. (0.1116-0.0461) 0 (0.08978+0.0461)
0.0655 0.1359
Now we have to calculate the pH of the solution.
Using Henderson Hesselbach equation :
![pH=pK_a+\log \frac{[Salt]}{[Acid]}](https://tex.z-dn.net/?f=pH%3DpK_a%2B%5Clog%20%5Cfrac%7B%5BSalt%5D%7D%7B%5BAcid%5D%7D)
Now put all the given values in this expression, we get:


Therefore, the pH of the solution is, 9.63
Umm yo no se no ablo engles
<u>Answer:</u> When bleach is mixed with water, it produces hypochlorous acid.
<u>Explanation:</u>
The chemical name for bleach is sodium hypochlorite. When this compound is reacted with water, it produces hypochlorous acid and sodium hydroxide.
The chemical equation for the reaction of sodium hypochlorite and water follows:

By Stoichiometry of the reaction:
1 mole of sodium hypochlorite reacts with 1 mole of water to produce 1 mole of hypochlorous acid and 1 mole of sodium hydroxide.
Hence, when bleach is mixed with water, it produces hypochlorous acid.