Question

A certain solution of methylamine has a pOH of 6.8, while a solution of pyridine has a pOH of 6.0. Which solution has a greater concentration of hydroxide ions?

Answer 1

Answer:

Pyridine solution has a greater concentration of hydroxide ions.

Explanation:

The pOH of the solution is defined as negative logarithm of hydroxide ion concentration in a solution.

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

• Higher the value of pOH lessor will be the hydroxide ion concentration and higher the concentration of hydrogen ions in the solution .
• Lower the value of pOH higher will be the hydroxide ion concentration and lower the concentration of hydrogen ions in the solution.

1) The pOH of the methylamine = 6.8

$6.8=-\log[OH^-]$

$[OH^-]=1.5848\times 10^{-7} M$

2) The pOH of the pyridine = 6.0

$6.0=-\log[OH^-]$

$[OH^-]=0.000001 M=1.0\times 10^{-6} M$

Pyridine solution has a greater concentration of hydroxide ions than the solution of methylamine.