Quandaries and Queries


Name: Margaret

Who is asking: Student
Level: Secondary

In a chemistry laboratory the concentration of one solution is 10% hydrocholoric acid (HCl) and that of a second soulution is 60% HCl. How many mL of each should be mixed to obtain 50 mL of a 30% HCl solution??

Any help is appreciated.

Thanks ahead of time,




Hi Margaret,

If the object is to have 50 ml of liquid, 30% of which is HCl then you need

50 x 30/100 = 15 ml of HCl.

If the 50 ml are obtained using k ml of the first solution then you also need 50 - k ml of the second solution. The first solution is 10% HCl and hence k ml of the first solution gives

k x 10/100 ml of HCl. The second solution is 60% HCl and hence k ml of the first solution gives (50 - k) x 60/100 ml of HCl.


k x 10/100 + (50 - k) x 60/100 = 15


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