The concentration of K^+ ions in 100 mL of 0.0500 M K_2CO_3 solution, in g L^{-1}, is A - VCE - SSCE Chemistry - Question 12 - 2006 - Paper 1

In a 0.0500 M K_2CO_3 solution, each formula unit of K_2CO_3 yields 2 K^+ ions upon dissociation. Thus, the concentration of K^+ ions is:

$[K^+] = 2 imes 0.0500 M = 0.1000 M$

To find the concentration in g L^{-1}, we need to convert moles to grams.

The molar mass of K is approximately 39.10 g/mol.

So, $ext{Concentration in g L}^{-1} = 0.1000 M imes 39.10 g/mol = 3.91 g L^{-1}$

Since 100 mL is 0.1 L, the concentration in g L^{-1} remains as 3.91 g L^{-1}.