You need to know that Ammonia 25% is 19.46M.
To calculate that, you need to know that out of 100 grams, you have 25 grams of Ammonia.
25 grams of Ammonia is 1.46 mols over 75 grams of water, also known as 75mL
1.46 mols/.075L =19.46
From there it's easy, let's make 1L of 2M ammonia. 19.46M×102.77mL =2M×1000mL
