Respuesta :
Answer:
(a)The solution is basic in nature.
(b)The solution is neutral in nature.
(c)The solution is acidic in nature.
Explanation:
pH value:
- The value of pH Neutral solution is equal to 7.
- The value of pH of Acidic solution is less than 7.
- The value of pH of basic solution is grater than 7.
The concentration of H⁺ ion's (pH) of a solution is the magnitude of negative sign of logarithm value of [H₃O⁺}, is called pH of that solution.
That is
[tex]pH=-log[H_3O^+][/tex]
We know that,
[tex][H_3O^+][OH^-]=K_w=10^{-14}[/tex] [ at 25°C]
Taking log both sides
[tex]log[H_3O^+]+log[OH^-]=logK_w=log 10^{-14}[/tex]
[tex]\Rightarrow - log[H_3O^+]-log[OH^-]=-logK_w=-log 10^{-14}[/tex]
[tex]\Rightarrow pH+pOH=pK_w={14}[/tex]
[tex]\therefore pH+pOH={14}[/tex]
(a)
[tex][OH^-]=3.8\times10^{-2}M[/tex]
[tex]- log[H_3O^+]-log[OH^-]=14}[/tex]
[tex]\Rightarrow pH-log(3.8\times 10^{-2})=14[/tex]
[tex]\Rightarrow pH-(-1.42)=14[/tex]
[tex]\Rightarrow pH=14-1.42[/tex]
∴pH= 12.58
since pH>7
The solution is basic in nature.
(b)
[tex][OH^-]=1.0\times10^{-7}M[/tex]
[tex]- log[H_3O^+]-log[OH^-]=14}[/tex]
[tex]\Rightarrow pH-log(1.0\times 10^{-7})=14[/tex]
[tex]\Rightarrow pH-(-7)=14[/tex]
[tex]\Rightarrow pH=14-7[/tex]
∴pH= 7
The solution is neutral in nature.
(c)
[tex][OH^-]=5.5\times10^{-10}M[/tex]
[tex]- log[H_3O^+]-log[OH^-]=14}[/tex]
[tex]\Rightarrow pH-log(5.5\times 10^{-10})=14[/tex]
[tex]\Rightarrow pH-(-9.26)=14[/tex]
[tex]\Rightarrow pH+9.26=14[/tex]
[tex]\Rightarrow pH=14-9.26[/tex]
∴pH= 4.74
Since pH<7
The solution is acidic in nature.