Question

What is [OH-] in a 0.0035 M HCl solution?

Answer 1

Hello!

The dissociation reaction of HCl is the following:

HCl(aq) + H₂O(l) → H₃O⁺(aq) + Cl⁻(aq)

The concentration of H₃O⁺ is the same concentration as HCl (0,0035 M). Now, we calculate the pH using the following equation:


`pH=-log(H_3O^(+))=-log(0,0035 M)= 2,46`

Now, we determine the pOH using the following equation:


`pOH=14-pH=14-2,46=11,54`

To finish, we apply the definition of pOH and clear for [OH⁻]:


`[OH]= 10^(-pOH)= 10^(-11,54)=2,88*10^(-12) M`

So, [OH⁻]=2,88*10⁻¹²

Have a nice day!