Question

1.You need standard aqueous HCl of about .04 M concentration. Explain why you need to dilute a whole number volume rather than use the precise volume required to give .04000M HCl. For example assuming you had .1164 M HCl you would dilute 75.00ml to 250.00 ml, rather than diluting 85.90 mL to the same volume.

2. Show the calculation of relative difference between the values 9.5x10^-5 and 8.8x10^-5.

Answer 1

1. Its always to dilute a whole number volume rather than use the precise volume to obtain a definite concentration. This is because if you start with a precise volume you need very accurate measuring apparatus to measure the volume. For eample if you are going to dilute a 89.90 mL solution, you need to have a measuring apparatus that can acuurately measure volumes upto 0.10 mL. On the other hand if you are selecting whole number volumes like 75.00 mL, 250.00 mL etc. you can make use of less accurate measuring apparatus which can measure accurately only upto 1 mL. So making use whole number volumes always saves time and precious time.