<PRE><B>Question 334336</B>
 How much pure hydrocloric acid must be added to 40 milliliters of a 50% solution to obtain a 75% acid solution?
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Equation:
acid + acid = acid
0.50*40 + x = 0.75(40+x)
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Multiply thru by 100 to get:
50*40 + 100x = 75*40 + 75x
25x = 25*40
x = 40 milliters (amt. of pure HCL needed for the mixture)
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Cheers,
Stan H.
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