Question

What is the molarity of 5.30g of Na2So3 dissolved 400ml solution?

Answer 1

5.30 grams of Na2SO3 is dissolved in 400 ml solution.

molar mass of Na2SO3= 2 X 23 + 32 + 3 X 16 =>46+32+48 => 126 g mol-1

So, 5.3 grams of Na2SO3 is 5.3/126 => 0.042063 moles =>0.042 moles

Volume of solution= 400/1000 L =>0.4 litres

Molarity of solution= (moles of solute)/( litres of solution)

molarity = 0.042/0.4 =>0.42/4 =>  0.105 M