Question

prepare 200 ml (m/20) aq solution of na2co3 (with explaination please)​

Answer 1

Answer:Molarity = no. Of moles of solute/ litre of solution

Since 100ml = 0.1 L

Therefore , 0.5 = no. of moles of solute/ 0.1

Hence,No. of moles of solute = 0.05 moles.

But , no. Of moles = mass of substance/ molecular mass of substance

So , 0.05 = mass of substance/ 106 = 5.3

Hence , mass or amount of sodium carbonate in litre of solution is 5.3

Calculation of molecular weight of sodium carbonate , = 23 *2 + 12*1 + 16 *3= 106.