What is the molarity of a 5.00 x 10^2 ml solution containing 21.1 g of potassium bromide (kbr) if the molar mass of kbr is 119.0 g/mol?

* number of moles :

1 mole KBr 119.0 g
? moles KBr 21.1 g

21.1 x 1 / 119.0 => 0.1773 moles

Volume in liters:

5.00 x 10² mL / 1000 => 0.5 L

Therefore:

M = moles KBr / volume

M = 0.1773 / 0.5

= 0.3546 M

The answer is true for your question.