Question

Calculate [H3O+] at 25 ∘C for each solution and determine if the solution is acidic, basic, or neutral.a.) [OH−] = 3.8×10−2 Mb.) [OH−] = 1.0×10-7 Mc.) [OH−] = 5.5×10−10 MPlease show the work and how you determine if the solution is neutral, acidic, or basic

Answer 1

(a)The solution is basic in nature.

(b)The solution is neutral in nature.

(c)The solution is acidic in nature.

Step-by-step 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

`pH=-log[H_3O^+]`

We know that,

`[H_3O^+][OH^-]=K_w=10^(-14)` [ at 25°C]

Taking log both sides

`log[H_3O^+]+log[OH^-]=logK_w=log 10^(-14)`

`\Rightarrow - log[H_3O^+]-log[OH^-]=-logK_w=-log 10^(-14)`

`\Rightarrow pH+pOH=pK_w={14}`

`\therefore pH+pOH={14}`

(a)

`[OH^-]=3.8*10^(-2)M`

`- log[H_3O^+]-log[OH^-]=14}`

`\Rightarrow pH-log(3.8* 10^(-2))=14`

`\Rightarrow pH-(-1.42)=14`

`\Rightarrow pH=14-1.42`

∴pH= 12.58

since pH>7

The solution is basic in nature.

(b)

`[OH^-]=1.0*10^(-7)M`

`- log[H_3O^+]-log[OH^-]=14}`

`\Rightarrow pH-log(1.0* 10^(-7))=14`

`\Rightarrow pH-(-7)=14`

`\Rightarrow pH=14-7`

∴pH= 7

The solution is neutral in nature.

(c)

`[OH^-]=5.5*10^(-10)M`

`- log[H_3O^+]-log[OH^-]=14}`

`\Rightarrow pH-log(5.5* 10^(-10))=14`

`\Rightarrow pH-(-9.26)=14`

`\Rightarrow pH+9.26=14`

`\Rightarrow pH=14-9.26`

∴pH= 4.74

Since pH<7

The solution is acidic in nature.