Final answer:
The number of mmol of HCl in 3.0 μl of 12 M HCl is 0.036 mmol.
Step-by-step explanation:
The number of mmol of HCl in 3.0 μl of 12 M HCl can be calculated using the formula:
mmol = (volume in μl) x (concentration in M) x (10^-3)
mmol = (3.0 μl) x (12 M) x (10^-3) = 0.036 mmol
Therefore, there are 0.036 mmol of HCl in 3.0 μl of 12 M HCl.