Question

When making 10X TBS (200mM Tris pH 8, 1.4M NaCl) the instructors realized that they did not have NaCl in a solid form. But they did have 3.5L of a 16.2% NaCl solution. How much of this solution did they use to make 1L of 10X TBS?

Answer 1

0.2 l.

Step-by-step explanation:

Concentration of NaCl on TBS = 1.4M

Molar mass = 23 + 35.5

= 58.5 g/mol

Density of NaCl in TBS = concentration * molar mass

= 58.5 * 1.4

= 81.9 g/l

Assuming in 100g of solution,

Mass of NaCl = 16.2 g

Volume = mass/density

= 16.2/81.9

= 0.198 l of NaCl solution is needed.