To find the concentration of hydronium ions, take 10 raised to the negative pH:
10^-9.56= 2.75 x10^-10M
To find the concentration of hydroxide ions, take 10 raised to the negative pOH: 10^-4.44 = 3.63 x10^-5M
I don't know about 14, but 15 is (4), because a liquid draws in heat to turn into a gas. 16 is (2), because to turn into a cold solid, something has to release heat.
Answer : The pH of buffer is 9.06.
Explanation : Given,

Concentration of HBrO = 0.34 M
Concentration of KBrO = 0.89 M
Now we have to calculate the pH of buffer.
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)
![pH=pK_a+\log \frac{[KBrO]}{[HBrO]}](https://tex.z-dn.net/?f=pH%3DpK_a%2B%5Clog%20%5Cfrac%7B%5BKBrO%5D%7D%7B%5BHBrO%5D%7D)
Now put all the given values in this expression, we get:


Therefore, the pH of buffer is 9.06.
1.it is readily available since hydrogen is a basic earth element and it's very abundant.
2. It doesn't produce harmful emissions.
Disadvantages
1.it is expensive. It is expensive because it takes a lot of time to separate the element from others.
2.it is difficult to store. Even moving a tiny bit of hydrogen would be very expensive.
3. It is highly flammable. Since it is a very powerful source of fuel, hydrogen can be very flammable.