Question

What are the concentrations of hydroxide and hydronium ions in a solution with a pH of 4.6?

Answer 1

Answer: 2.5 × 10⁻⁵ M H₃O⁺ and 4.0 × 10⁻¹⁰ M OH⁻

Step-by-step explanation:

∵ pH = - log[H₃O⁺]

∴ 4.6 = - log[H₃O⁺].

∴ log[H₃O⁺] = - 4.6.

∴ [H₃O⁺] = 2.51 x 10⁻⁵.

∵ [H₃O⁺][OH⁻] = 10⁻¹⁴.

[H₃O⁺] = 2.51 x 10⁻⁵ M.

∴ [OH⁻] = 10⁻¹⁴/[H₃O⁺] = 10⁻¹⁴/(2.51 x 10⁻⁵ M) = 3.98 × 10⁻¹⁰ M ≅ 4.0 × 10⁻¹⁰ M.

Answer 2

Answer : The concentration of hydroxide and hydronium ion is,
`3.9* 10^(-10)M` and
`2.5* 10^(-5)M`

Explanation: Given,

pH = 4.6

pH : It is defined as the negative logarithm of hydrogen ion and hydronium ion concentration.

`pH=-\log [H_3O^+]`

First we have to calculate the
`H^+` concentration.

`pH=-\log [H_3O^+]`

`4.6=-\log [H_3O^+]`

`[H_3O^+]=2.5* 10^(-5)M`

Now we have to calculate the pOH.

`pH+pOH=14\\\\pOH=14-pH\\\\pOH=14-4.6=9.4`

Now we have to calculate the
`OH^-` concentration.

`pOH=-\log [OH^-]`

`9.4=-\log [OH^-]`

`[OH^-]=3.9* 10^(-10)M`

Therefore, the concentration of hydroxide and hydronium ion is,
`3.9* 10^(-10)M` and
`2.5* 10^(-5)M`