Question

To prepare 100g of 19.7% by weight solution of NaOH.how many grams each of NaOH and H2O are needed?

Answer 1

%by mass = (mass solute)/(mass solution)
% w/w = 19.7g NaOH in 100 g solution.
% w/w = 19.7 g NaOH in [19.7g NaOH + (100-19.7)g H2O].