Question

is gravimetric analysis or colourimetry more accurate when it comes to precipitation reactions where only around 6g and 100ml of the products are used?

Answer 1

I'm inclined to think gravimetric analysis would be better. Six grams is measured easily and accurately as is 100 mL. In most cases colorimetric analysis works best for dilute solutions; therefore, any small error in measurement would be magnified when converted to the full six gram sample.