Question 804760
You have 3 liters of 28% solution of sodium hydroxide. What is the amount and concentration of sodium hydroxide you must add to this to end up with 7 liters of 48% solution?
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You have to add 4 liters to make 7 liters.
3*28 + 4*C = 7*48
84 + 4C = 336
4C = 252
C = 63%