That depends on the concentration of the solution. Milligrams is a unit of mass, a teaspoon is a measure of volume, you can't convert between the two without knowing the concentration, or the density.
Approximately 5,000 milligrams.
1 gram are 1000 miligrams.
10 milligrams in 1 centigram.
1 gram = 1,000 milligrams
Multiply by 1000. So there are 1000 milligrams in 1 gram.
Since 1 Gram is equal to 1,000 miligrams, 7.5g = 7,500mg.
7
5 gm of water in a teaspoon
That is 1 teaspoon.
2.66 tbsp 1 tablespoon = 3 teaspoon 1 teaspoon = 0.33 tablespoon
That is 1 standard teaspoon
1 teaspoon is 5mls, so 2.5mls would be 1/2 teaspoon.
1 teaspoon is 76 drops. 1/4 teaspoon is 19 drops.