The amount of the solute is constant during dilution. So the mole number of HCl is 2*1.5=3 mole. The volume of HCl stock is 3/12=0.25 L. So using 0.25 L stock solution and dilute to 2.0 L.
2 hydrogen and 1 oxygen makes water
Answer:

Explanation:
To find the weight (W) of the pond contents first we need to use the following equation:
(1)
Where m the mass and g is the gravity
Also, we have that the mass is:
(2)
Where ρ is the density and V the volume
We cand calculate the volume as follows:
(3)
Where L is the length, w is the wide and d is the depth
By entering equation (2) and (3) into (1) we have:

Therefore, the weight of the pond is 6.65x10⁶ lbf.
I hope it helps you!