300 g of a 30% (w/w) NaOH solution is mixed with 500 g of a 40% (w/w) NaOH solution. If the density of the resulting solution is 2 g/mL, what is the % (w/v) concentration of NaOH in the final solution?

Question

Accepted Answer

72.5. Mass of NaOH from first solution = 30% of 300 = 90 g. Mass of NaOH from second solution = 40% of 500 = 200 g. Total NaOH = 290 g. Total solution mass = 300 + 500 = 800 g. Volume of final solution = 800 g / 2 g/mL = 400 mL. %(w/v) = (290/400)*100 = 72.5%. The question provides density to allow w/v calculation; straight w/w would give 290/800*100 = 36.25%, not among the options.

300 g of a 30% (w/w) NaOH solution is mixed with 500 g of a 40% (w/w) NaOH solution. If the density of the resulting solution is 2 g/mL, what is the % (w/v) concentration of NaOH in the final solution?

Solution

Related JEE Advanced Chemistry questions