Question #93135

It is required to prepare 1250kg of a solution composed of 12 wt. % ethanol and 88 wt. % water. Two solutions are available, the first contains 5 wt. % ethanol, and the second contains 25 wt. % ethanol. How much of each solution are mixed to prepare the desired solution? Check your answer

Expert's answer

1.Ethanol balance

@$A(5/100)+B(25/100)=M(12/100)@$

@$0.05A+0.25B=0.12M@$

@$A=(150-0.25B)/0.05=3000-5B@$

2.Water balance

@$0.95A+0.75B=0.88M=0.88*1250=1100@$

@$0.95A+0.75B=1100@$

Sub.(1) in (2)

@$0.95(300-5B)+0.75B=1100@$

@$2850-4.75+0.75B=1100@$

@$4B=1750@$

@$B=437.5kg@$

Sub B in (1):

@$A=3000-5*437.5=812.5kg@$

Answer:812.5kg 5% and 437.5kg 25% ethanol

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